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Permethrin Soak Method Guide

Permethrin Soak Method Guide

Permethrin is an insect repellant and insecticide that bonds to fabric and can be used on your clothes, tent, or hammock to prevent Lyme Disease, Rocky Mountain Spotted fever, or the Zika Virus by killing ticks, mosquitos, and insects that land on your stuff. The liquid Permethrin application techniques discussed below are only for treating clothing or outdoor gear and are not intended for human or animal use.

Soak or Spray: Two Ways to Apply Permethrin to Clothing and Gear

There are two ways to self-apply Permethrin to clothing, tents, and hammocks: spraying or soaking.

Spraying your clothes or gear is a convenient way to treat them with Permethrin if you have a limited number of items. To learn more about the spray method using pre-mixed Sawyer Permethrin, see Treating Your Clothes with Permethrin.

Soaking your clothes in Permethrin is the second way to treat clothing or outdoor gear and can be useful when you have bulky or a large number of items to treat. Before you begin, be sure to read all labels and documentation that comes with your Permethrin solution to determine if it is legal to use for this purpose in the United States. If in doubt, read the MSDS or call the manufacturer and ask.

Permethrin treated clothing kills the ticks that land on it as long as you retreat your clothing periodically to maintain its effectiveness
Permethrin-treated clothing kills the ticks that land on it as long as you retreat your clothing periodically to maintain its effectiveness.

How long does Permethrin Treated Gear and Clothing Remain Effective?

Both methods of Permethrin self-application, spraying, and soaking, remain effective for 6 weeks or 6 washes. You can prolong the effectiveness of self-applied Permethrin by storing permethrin-treated gear or clothes in black plastic bags (since sunlight breaks down Permethrin) or by hand washing items because the agitators in washing machines also accelerate its decay.

There’s anecdotal evidence that soaking your clothes with Permethrin instead of spraying is effective longer, but there isn’t any publicly available laboratory to support that conjecture. It’s just common sense that soaking will penetrate both the inside and outside of a garment while spraying it will just cover the outside.

Long-Lasting Insect Shield Permethrin Treatment

If you want a longer-lasting treatment that will last up to 70 washings, you can send your clothing to a company called Insect Shield which has developed a proprietary process for Permethrin application that lasts longer than what you can do at home. I have no idea what they do that’s different, which is probably why they keep it a trade secret. Here’s a link to the Insect Shield order form that you use to send clothing you want them to process. The prices are listed on the form.

Yes. It is worth paying Insect Shield to treat your clothes with a longer-lasting Permethrin treatment, especially if ticks and Lyme Disease are a concern. I regularly send them pants, shirts, gaiters, and socks to be treated. They don’t treat underwear and you have to treat your gear yourself. As for gear, I don’t bother, although you could convince me that it’s worth doing on a hammock or a tent floor.

Permethrin with High Concentrations of Petroleum Distillates

You want to avoid buying permethrin with Petroleum Distillates in it. These can leave a greasy film on any gear or clothing you treat with it, which is most unpleasant and may cause skin irritation. We can vouch for Sawyer’s Permethrin, with is premixed to the right concentration for treating clothing and gear, and Martins 10% Permethrin Concentrate (having used them many times on my own gear and clothes).

Why would you soak clothes with Permethrin instead of spraying them?

Soaking can be more convenient if you have bulky items (like a tent or hammock) or you want to treat or many articles of clothing. Soaking is also likely to provide better coverage than spraying, including the inside and outside of garments than spraying which may miss spots. If an insect avoids the outside of a garment and makes it to your skin, there’s a good chance that it will still be killed if the inside of your clothing has also been pre-treated with Permethrin.

Martins Permethrin 10 percent
Martins Permethrin Concentrate

What is the most economical way of soaking gear and clothes with Permethrin?

While you can soak items in the pre-mixed 0.5% Permethrin Solution sold by Sawyer, it is more economical to buy a highly concentrated Permethrin solution like Martins 10% Permethrin and dilute it down to the recommended 0.5% strength solution recommended for treating fabrics. Concentrated permethrin solutions are also available in many feed and hardware stores but you want to be careful to avoid any permethrin or permethrin that includes petroleum distillates. (See below)

While often intended for veterinary or agricultural use, highly concentrated Permethrin solutions diluted to a 0.5% Permethrin concentration are thought to be as effective at killing insects as the pre-mixed 0.5% Sawyer Permethrin solution. No one knows definitively in the absence of laboratory testing, although anecdotal accounts from many people suggest this to be the case. Follow all manufacturer product instructions and use them at your own risk.

How to dilute concentrated permethrin.

If you choose to dilute a concentrated form of permethrin like Martin’s 10% Permethrin, you need to reduce it to the 0.5% concentration recommended for clothing treatment. Many concentrated Permethrin solutions come with a built-in measuring cup for this process.

I prefer bagging up the clothing I plan to treat with Permethrin in 1 gallon freezer bags before pouring the Permethrin solution over them and letting them sit and soak.
I prefer bagging up the clothing I plan to treat with Permethrin in 1 gallon freezer bags before pouring the Permethrin solution over them and letting them sit and soak.

If you use a 10% Permethrin concentrate, you want to dilute it with 19 parts water and 1 part of 10% permethrin concentrate to produce a 0.5% Permethrin solution. For example, if you wanted to make a gallon (128 ounces) of a 0.5% Permethrin solution using water and a 10% Permethrin solution, you’d mix 6.4 ounces of 10% Permethrin solution with 121.6 ounces of water. If you do this using a 1-gallon plastic water bottle (shown above), you’d pour off 6.4 ounces of water and replace it with 6.4 ounces of the 10% Permethrin concentrate. Shake well to mix it up.

I recommend wearing protective gloves when working with Permethrin in any concentration, keeping it away from all animals, food, and water supplies, and only using it in a shady, well-ventilated, outdoor area. All of the containers used to hold Permethrin should also be properly labeled and disposed of as recommended on the product label by the manufacturer.

 

Pour enough Permethrin solution to soak each item and then let sit for a few hours so that ot fully soaks the material.
Pour enough Permethrin solution to soak each item and then let sit for a few hours so that it fully soaks the material. Sawyer recommends 3 ounces of 0.5% Permethrin solution per garment. But you can add more if it’s needed to soak the item as long as it’s diluted to the same 0.5% concentration.

What’s the best way to soak your clothes with Permethrin?

While you can dip your clothes in a large bucket of 0.5% Permethrin (some people hold Permethrin Parties to do this with friends), I prefer bagging them individually in 1-gallon freezer bags and pouring a smaller quantity of Permethrin solution into each bag. This eliminates having a large amount of leftover Permethrin that is complicated to safely dispose or store. It also prevents the accidental inhalation that mist if you spray rather than soak your garments.

I then massage the liquid into the garment and let it sit for a few hours to fully soak through all the layers of clothing, before pulling it out of the bag and hanging it up to dry in the shade. Sunlight breaks down Permethrin, so you should avoid drying Permethrin-soaked clothing on a clothesline in the sun. Just let it air dry.

Once dry, the Permethrin treated clothing is ready to wear
Once dry, the Permethrin-treated clothing is ready to wear.

Once the garments have dried, they’re ready to wear. There’s no need to wash them or dry them in a drier before use. Doing so will only begin to break down the Permethrin that has bonded to the garment’s fabric.

Can you soak clothing using pre-mixed 0.5% Sawyer Permethrin?

Absolutely. It can be far more convenient to soak your clothes using Sawyer Permethrin since it’s pre-mixed to the correct 0.5% concentration without having to dilute concentrated Permethrin, safely dispose of contaminated containers, or left-over Permethrin solution. It’s just more expensive.

How should you dispose of unused Permethrin solution?

If you have leftover Permethrin solution, please don’t pour it down the drain. Permethrin is deadly to fish and harmful to people if ingested in its liquid form. The safest way to dispose of it is to let it evaporate. You can also store any remainder in a bottle for future use.

Liability Disclaimer: The author of this article and website is not responsible for any damage, personal injuries or death as a result of the use of any information, maps, routes, advice, gear or techniques discussed herein. All activities are carried out at your own risk. 

Updated 2023.

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81 comments

  1. Thanks for the info. I saw your advice that treatment lasts 6 weeks or 6 washings. Are the washings in cold water? Should I put them in the dryer or drip dry them like in the application phase?

  2. I use permethrin on bandanas for my dogs to keep ticks away.
    Seems to work well.
    My dogs have always been my best hiking buddies.
    Ticks here in the northeast are a huge problem.

  3. I use Martins in the 36.8% strength. 1 tablespoon of this added to 12 ozs of water makes a 1.5% solution (math confirmed by a pharmacist/hiker), which is what the military uses. Even though the label says “contains petroleum distillates”, I’ve been using this for years and never found it to leave a greasy residue. It stinks at first, but once the distillates evaporate, the vast majority of the smell goes away. The petroleum distillates are what allows the permethrin, which is not soluble in water, to dissolve. If you use a brand which does NOT include petroleum distillates, be sure to shake your spray bottle or stir your soaking tub frequently, otherwise the permethrin will separate out (since it’s not a true solution). I also think the petroleum distillates allow the permethrin to bond to the clothing better than a simple water-based emulsion would.

    Also, I prefer to wash the garments using cold water and NO detergent, which believe it or not seems to get the dirt and dried sweat out well enough.

    I definitely agree with wearing protective gloves, doing this OUTSIDE, and ideally wearing a face mask (anybody got one of these?) and standing up wind from the clothing as you spray. This stuff is a neurotoxin until it is dry, but once fully dried is considered safe. I also agree with not putting this stuff in the washing machine!!

    • > and ideally wearing
      > a face mask (anybody
      > got one of these?)

      Oh, you!

      :-D

    • I fill a tall tote with about 12 gallons of the mixture and soak and stir several items for a few minutes, wring out and hang to dry. If necessary I’ll toss in the dryer to finish off the drying. Any left over mixture i pour into a large (5 gal) sprayer and treat shoes, hammocks, camp chairs, outdoor furniture cushions, tents, etc. Sprayer is labeled for only this use. If my truck seats were fabric I’d treat those too! I do this at least twice a year. Seems to be effective maybe 12 washings – hard to sure – but definitely more than 6. . I tried EVERY method I could find to prevent chiggers and had very little success until I discovered permethrin. Someone else mentioned smell. There is a slight smell Immediately after treatment that goes away after first wash. I wash gentle cold with gentle soap, dry medium heat. I have sensitive skin and eyes and not at all affected by permethrin treatment. Permethrin is a miracle that has given me back the outdoor activities I love!

    • Nice review and suggestions, have saved it for when I am about to start my AT next April.
      Best Regards

    • I have a question. How long do you soak the items?

  4. I’m just curious, my back sweats a lot while backpacking no matter what kind of pack I use. I can’t stand Deet on my skin or clothes. I bought Sawyers to spray on my clothes. But I am wondering if permethrin will be absorbed in my skin, and even more so if I soak them. Any thoughts or advice ? Thanks

    • It won’t be absorbed by your skin. Once it dries that first time after application it’s bonded to the fabric. I regularly wade/stream cross in permethrin-treated pants without issue or loss of efficacy. I would suggest sending them out to Insect Shield however for longer lasting treatment that will surviuve 70 washings.

      • Great article and perfect timing. I have been pulling ticks off my GSD (who loves to bushwack!!) for two months; and my wife developed the classic halo around an imbedded tick I found on her back side. She just finished her doxycycline script but not without huge side effects.
        When I hiked the AT, I treated all clothes and my gear with military grade permethrin , what we treated our uniforms before deployment. I recommend against this; imagine how bad a thru-hiker smells. Now triple it with military grade permethrin. It really was a “solo” hike for me!!

  5. i had lyme disease last year and that is something you definitely want to avoid. I lost the entire month of July 2020 laying on the couch moaning and lost 14 lbs. the studies show this works. I did not find another tick on my since starting doing this to my clothes. Today I am retreating for this year.

  6. Advice please, I seem to be a “tick magnet “. I can be with 10 people walking in the woods and I will be only one with ticks and they grab on quick. I’ve been told Carbon Dioxide our bodies give off attract ticks. Well I’ve used everything on my body on my clothes and I still will be only one with them. I mean multiple ones. Any ideas please I love the outdoors.

    • Just wear long pants and gaiters. Permethrin helps kills them if they latch onto your clothing before they can bite you.

    • There are many options on clothing pretreated with permethrin. I was hiking with my brother in law in a place Arkansas that should have been named Tickville. I watched large, hungry ticks crawl up my pants and once they got to knee level, they started walking in circles and fell off. If you use gaiters or tuck your long pants into your socks, you get the satisfaction of watching them croak on the outside of your garment, rather than the inside.

      There are ways to manage the tick scourge. Permethrin works! I love dead ticks!

    • Hey Jewel, me too… I get em when nobody else does. And ALOT. Found out that Type A blood is something they’re more attracted too by 30 %. After two tick born illnesses and loving the outdoors and nature, I’ll definitely be doing something different. Good to know of these ideas for sure! Good luck yourself!!!

  7. Philip do you treat your hat and headnet also?

  8. How do you wash your permethrin treated clothes after wearing- if you’re not supposed to put them in the washer and the water is not supposed to go down a drain?

  9. The Amazon link to Martins Permethrin 10% no longer works. Do you have another source?

  10. I just tried the gallon bag method and I can’t believe 3 oz. is enough to “soak” any garment bigger than a sock. How much do you really put in for long sleeves shirts and carhartt pants? Trying to swish the garment around inside the bag is really hard and I’m having trouble believing the solution is getting to the entire garment. Can you please give a more detailed explanation? Thanks.

    • So put more in. It’s all the same percentage of concentration. Let any remaining in the bag that is not soaked dry in the sun. Whatever you do, don’t pour it down a drain.

      • After a lot of additional pouring and swishing and pouring and swishing and leaving the garments overnight, most of the clothes had huge dry spots. No matter how much I tried to mangle the garment in the bag, the solution only soaked into the part it touched when poured. Also, I don’t understand leaving the garment in the bag for hours. Once the solution is in the cloth, don’t we want to dry it? I think I’ll look for a safe place to spray, because now I have a lot of partially treatment, wrinkled clothes I can’t trust to kill ticks.

        Thanks for all the other info, tho. It was very informative. All the equipment is drying — no drain! BTW, there are ziplock bags in 2.5 gallon capacity, better for larger items.

        • How tightly packed is your bag? If the garment is too compressed it will prevent liquid from getting into the folds, like with tie dying. You want it to be able to move around a bit and be a loose wad/ball in the bag, not all squished up. You could also try spraying to get all surfaces roughly covered, then put the sprayed garment in a bag with a bit extra to squish around to make sure you have good coverage.

    • My experience: Using 10% diluted to about 0.9% (1.5 oz concentrate added to a empty 16.9 oz bottle of water; slowly fill with water (avoid foaming), shake vigorously, dump into a bucket), a single cotton t-shirt will absorb almost the while pint. Wring it out and you’ll recover most of the liquid.

      Mixing 5 pints I was able to thoroughly soak two pairs of pants, 4 t-shirts, and two hats (though the last hat didn’t get as wet as I would have liked).

      Doing this, the dried clothes were a little stiffer than my experience with Sawyer spray. Next time I’ll do 1 oz of 10% concentrate plus 15.9 oz. water to get to about 0.6% solution.

  11. Permethrin products that contain petroleum distillates — several times, you warn about avoiding these, but you never explain why. What’s the reason?

    The Martins 10% listing does not say specifically that it’s for clothing. Some brands (Sawyer, JT Eaton Kills) specifically say they’re appropriate for clothing. Is there a significant chemical difference?

    Does it need certain chemicals to bind to the clothing or will all permethrin do that?

    • The distillates can cause an allergic reaction.
      Martins is water-based. Look up the Material Data Safety Sheet.
      I can’t answer your other questions definitively, so I won’t.

  12. Hi, thanks for this article! I live in Nova Scotia, where finding permethrin is quite difficult due to Canadian regulations. My husband bought some “LIQUID INSECT SPRAY EMULSIFIABLE CONCENTRATE” that contains 12.5g/liter permethrin. It’s been a really long time since chemistry and I’m just not sure what percentage concentration that means.. tried googling and couldn’t find an easy answer, which is all I can deal with lately! I would really appreciate any help or illumination you could provide! Thank you!

    • 1 liter of water weighs 1,000 grams. So 12.5g/liter would be 1.25% concentrate. Someone correct me if it’s not that simple of a calculation.

      • As far as this fuzzy-brained math major is concerned, you are correct. Mix 2.5 times as much water to get to .5%. For example, mix 1.25 L water with .5 L of your product to end up with 1.75 L for treating clothing.

      • Thank you so much!! I was thinking that was probably the case.

  13. I spend a lot of time in the woods, and as someone who has experienced the nightmare that is Rocky Mountain Spotted Fever (18 months later I am still dealing with residual effects), I take tick protection very seriously. I had a long conversation just yesterday with Larry Dapsis, an entomologist in Massacheusetts who specializes in ‘Tickology”. I learned a lot.

    Soaking clothes in Permethrin is an old-school method. It is messy, labor-intensive and is not necessary to achieve thorough tick protection vs. spraying. The idea that “more is better” by soaking is not valid. His recommendation is to use a 0.5% solution and spray. Rolling pantlegs inside-out up to knees and spraying is fine. I have done this for years. Proper spraying of clothing will provide 90% protection.

    The biggest obstacle he faces in dealing with the public is with toxicity. As soon as people see the word, “insecticide”, a red flag goes up and they look to other solutions, like essential oils (which do little to nothing, and can actually be quite dangerous to use). Permethrin toxicity to mammals (excluding cats) is extremely low when properly used.

    He did NOT recommend spraying dogs with Permetherin. He highly recommended Seresto collars or Advantix. I used Seresto colors for years with my Lab and they worked great. I stopped using them when she developed a skin irritation on her neck….a reddened quarter-sized area on her skin with loss of fur. He said this is rare, but does sometimes occur. I may re-visit the Seresto again, since it worked so well until this one incident, but I have been using Frontline Shield with very good results. Personally, I will not give my dog any of the ingestible flea/tick treatments. Anything thing that is directly metabolized by the liver is not a good idea, IMHO, especially when topical treatments have worked so well.

    Back to clothing and gear, the entomologist spoke highly of Insect Shield. He has worked with the owner of the company and highly recommends them. I may go this route, after they answer some questions I have.

    In the meantime, I will be mixing and spraying Permethrin on my clothes and gear. it works great, and here in the Southeast, we need all the help we can get to battle ticks.

    As far as washing treated clothes and gear, i have always used front-loader machines, NOT top-loaders with agitators. I wash in cold water with detergent, dry on low heat and have seen no detrimental effects in doing so.

    The Interwebs and full of misinformation about just about everything, including ticks. Sorting fact from fiction, hard data from anecdotes can be very frustrating. I HIGHLY recommend watching the following video with Mr. Dapsis, subscribing and watching his other videos as well.

    • Our dog gets the same irritation from his Seresto collar and we’ve found that putting a small bandana (the kind you thread the collar through) on the Seresto collar seems to cover just enough of the collar to protect that patch of skin without interfering with the effectiveness of the collar overall. His spot is under his chin where the collar gets into a sort of crease and I think it’s something about being trapped in that skin fold that causes the issue. The extra weight of the bandana helps keep things oriented properly, too, so the covered section is always where the irritation is.

      We do change for a fresh collar a bit earlier than the packaging says (I think it says 8 months and we use a new one every 6 months?) but that’s mostly paranoia. Ticks are gross.

  14. I bought Martin’s 10% to dilute as you suggest. However I now see that the Martin’s website says that this is not to b used on clothing because it contains ingredients that should not come in contact with skin. They say they have a different permethrin product for this purpose.
    What do you know anything about this?
    Thanks!

    • Nope and I didn’t see that notice anywhere on their website, which is:
      https://www.controlsolutionsinc.com/martins
      Here’s a link to their Safety data sheet.
      https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/Martins_Permethrin1_10_MSDS.pdf
      It is true that you don’t want to get liquid permethrin on your skin, which is why I recommend wearing gloves when applying it. But once it dries and bonds to the fabric of your clothing, it’s in a very different chemical state. Even more so after its first wash.

      But if you have any doubts, buy the sawyer permethrin product or send you stuff to Insect shield for the longer-lasting treatment.

      If you could supply a hyperlink to where you saw this notice I’d appreciate it.

      • Thank your reply. On second glance, it may not be an official Martin‘s page, however I got to it by searching Martin’s permethren 10% FAQs. I believe the question about spring and clothing is the 14th question if you scroll down the page.
        https://www.domyown.com/martins-permethrin-10-questions-pq-2124.html

        • I think it’s marketing bullshit so you buy their own product. Isn’t obvious….?

        • The 14th question refers to a kit to treat one set of clothing. It looks like a civilian version of the kits the military has to treat the same. The kit consists of a ziploc type plastic bag, a small bottle of permethrin that gets mixed with a half liter of water and then the garment goes in the bag. It’s nothing you can’t do at home with what you already have on hand. Although there is some slight difference in the chemicals mixed with the permethrin in the military kits vs. most bulk permethrin commonly available, doing it yourself is a viable and cheaper option.

        • My first thought was that it was a marketing gimick, but if the products do indeed contain different chemicals, no, I wouldn’t say this is necessarily obvious. I’m not familiar with the different chemicals used or their possible adverse health effects, so I just thought I’d check to see if you knew more. Thanks.

        • How do you know the products contain different chemicals? Because they said so? The thing that matters is that martins is water-based, not petroleum-based, which is the substance that tends to irritate people sensitive to it.

        • I spent quite a bit of time a few years ago trying to chase down the exact formulation of the permethrin the military uses since they make kits that will treat a set of garments that will last the lifetime of the garment, whereas the Sawyer and Martin’s stuff says six weeks or six washings. I chased down government paperwork on them and also the MSDS sheets and bought some of the military kits as surplus.

          The information on the Martin’s kits and the military ones use different fifty cent words (with inflation, I guess they’re now five dollar words!) to describe the permethrin and associated chemicals in the mix. The military uses 40% and most of the civilian bulk versions top out at 38.7% permethrin and again, the MSDS sheets use different five dollar words to describe what’s inside. The 40% stuff costs about twice as much as the 38.7% but there is some difference in the formulation.

          Usually, I set up a production line, mix a gallon of the noxious stuff and start treating a bunch of things in the closet that haven’t yet been treated. The surplus military kit allows me to be lazy and easily treat that one new garment I just bought.

        • I carefully chose the words “I spent quite a bit of time a few years ago trying to chase down…” Back when I was doing the chasing down, I might have worded it, “I did my own research…”, however, these days the term “I did my own research…” means “I wasted time on Facebook until I found someone who agrees with me…”

      • I would add one caveat to your advice about soaking clothing and then letting it dry before wearing it. I learned the hard way that “dry” means dry; it does not mean damp or “nearly dry.” Permethrin, as you say, is a neurotoxin and you definitely do not want your skin to make contact with it. Fortunately, in my case, it was only the socks that had not dried completely. The garment must be COMPLETELY DRY to avoid contact with the neurotoxin. I would suggest that, when in doubt, let it dry a little longer.

        • It’s a neurotoxin for bugs…but yeah let it really dry. I thought that was obvious, but then this is merica!

        • Philip Werner says in a reply that “It’s a neurotoxin for bugs”. Hate to tell you this, but a neurotoxin is a neurotoxin, bugs, people, dogs, you name it, pretty much. The difference between the active ingredients of neurotoxic chemical warfare agents and pesticides is two-fold, the concentration and the targeted organism. Other than that, they both work the same. Once it has dried and bonded to the fabric, the concentrations of Permethrin which can be absorbed by the skin is minimal, even when perspiring, and is not toxic to an organism the size of a human. But this is why the concentration is so low, to maintain that level of protection. The amount of product required to kill insects is much less because of their body size.

  15. I don’t really want to spray all my clothes with Permethrin. I’d prefer to spray just shoes and socks…but I guess I will if I really have to, but if I spray just shoes
    And socks will that be enough to repel mosquitoes while
    Camping in woods

  16. Hi Phil,

    Im not the best at math but your ratio makes sense to me. But page 18 of the Martin’s 10.00 percent (quart size) doesnt seem to match. It states: …”dilute at a rate of (1) part concentrate in 19 parts water (6.7 ounces per gallon) (0.5%).

    Can you help reconcile this difference?

    • Nope sorry. You’ll have to consult with someone under 40.

      • I’m definitely over 40, but I was a math major, so here goes…

        You have a 10% solution, which is 1/10 permethrin. You’re asked to dilute it so that your new solution is at 1/20 strength, which is 5%. Since your solution was originally at 10% permethrin, or 1/10, divide your 5% result by 10 and you get a final permethrin concentration of .5%. Another way to look at it is if you divide 10 by 20, you get .5.

        • Thanks, Grandpa. With your explanation, the 6.7 ounces per gal makes more sense to me than Phil’s 6.4. But I imagine the small difference is negligible.

      • I am 157.5% of 40…

        It’s a common error, seen others do it and done it myself.

        You can look at 1/20 as representing 1 part taken from a total 20 parts, division is like a form of subtraction.

        To remind ourselves of this, think of the relationship of 1 to 2 as in 1/2, I think when the denominator gets larger it throws us off.

    • I think the math says original post is correct. I don’t see a way to come up with 6.7. A way to look at it is:

      32 oz @ 10 % has a total of 3.2 oz permethrin. (32 x 0.10)
      1 oz at 10% has 0.1 oz permethrin (1 x 0.1)
      Desired result of 1 gallon, 128 oz at 0.5% needs a total of 0.64 oz permethrin. (128 x 0.005)
      6.4 oz of 10% solution in added to 121.6 oz water

      • Good catch.

        The Martins label has a little chart for mixing various concentrations. It says to mix 1:19 at 6.4oz per part for 0.50%. What they didn’t do was provide that 19 x 6.4 =121.6 as you did. If they said 6.7oz in another document that’s an error on their part.

        • However, assuming Phil was adding the 6.7oz to 128oz of water that’s also correct to within 2/100oz.

    • Rita, actually it turns out that adding 6.7oz to a full gallon (128oz) is the same ratio as adding 6.4oz to 121.6oz in order to make a gallon, to within an insignificant difference.

  17. So, we used a sprayer to spray our tent, but it is spotty. Anyone else have a problem with spottiness? Don’t know if it is the chemical formulation or the spraying technique, but now I am afraid to spray my clothes.

    Maybe best to soak in a zip lock — at least, theoretically, everything would be the same color.

  18. I am treating my several items of clothing for a winter trip to Guatemala and I’m afraid that my clothes will not dry properly this late in the season as it is close to freezing outside during the day, and goes below freezing at night. I had intended on bringing my items inside for the nights (placed in a ziplock) so they don’t freeze dry, as I don’t know if that will affect the efficacy of the permethrin , and then putting them out during the day when it warms up. Do you have any experience with the affect of freezedrying during permethrin treatment? We will only have about 3 more days before the weather turns cold again and Im’ afraid my items will not dry before then, even if I hang them out first thing every morning. I have assumed I cannot hang these inside to dry, but correct me if I’m wrong. Thanks for any feedback! All the Best Christine

    • I would bring them inside. You just don’t want to spray indoors. What you describe as “freezedrying” isn’t freeze drying.

    • I know this is too late for your trip but you can dry them indoors. It doesn’t have to be outside. The caveat to that is if you have a cat. The liquid permethrin is quite toxic to them but the dried clothing is not.

  19. Hi Phillip, thanks for an excellent article.
    I was wondering, would this also work for fleas? As in they would get on the clothes and die, does the dried pemethrin still work so strongly?

  20. Also, how long does it take for sunlight to break down permethrin in treated clothes, if you know? You said away from sun, it lasts for about 6 washes. I’d be really grateful for your reply, as I am in the sun a lot but also want protection from fleas.
    Thank you!

    • Yes, it will protect from Fleas (it’s an ingredient in a lot of pest products for dogs).

      I can’t speak for others experiences but I can tell when I’m hiking and the permethrin is starting to “wear off”. It’s not like a light switch where one day it works and the next it doesn’t. As far as the sunlight goes I would just avoid hanging/storing the treated clothes in spaces regularly exposed to direct sunlight. Obviously it’s exposed to the sun when you’re wearing it – not a concern.

  21. This is a great article. Thank you!
    I am wondering why it’s not a good idea to put permethrin treated clothes in the washer? Is it bad for the washer?
    Thank you very much.

    • I put mine in the washer all the time. Not sure where you heard it was bad.

      • That’s good news! Thank you very much! I think I misunderstood a comment above about not putting the permethrin in the washer.

        • I use the washing machine but air dry instead of using the dryer to reduce the mechanical friction that tends to wear off the Permethrin coating. I think it helps to extend the protection.

          I’m assuming that if the treated garments are just hanging in the closet, the Permethrin doesn’t degrade. Do you know anything different, Phil?

        • Hanging them in the closet won’t degrade te Permethrin. Just bright sunlight.

  22. Phil,

    I’ve decided to use the soak method for my cloths and here is my question.

    Tractor Supply carries Martins Perethrin in 13.3%.

    Spoke to sales associate and he said it is used to mix and spray animals. Is this okay to use? Is all Perethrin the same?

  23. Is there any reason permethrin can not be put directly into the fabric softer dispencer when washing forestry uniforms to go out to the field in?

  24. I am trying to soak my clothes in a tote. I had to use 48oz Sawyer and my 5 outfits are still not saturated. Sawyer customer service said not to dilute with water, but a different brand did and those are fully saturated (also 0.5%; 8oz solution to 16oz water). Would adding water harm the effectiveness since it’s twice the amount of solution needed for my 5 outfits??

  25. Michael Brouillette

    I’m enjoying all this Information and input from all my fellow Hiker’s and I’m glad I was smart enough to post and ask my questions and finding a wash in solution like the waterproofing I get for my gear. Now after reading everything here I’m sitting here wondering if maybe if I just get a five gallon bucket with a lid from Home Depot might be a better way to start instead of plastic bags. I’m wondering or thinking about maybe if I get a five gallon bucket I can either put the clothes or gear in the bucket first then pour in the permethrin and let it start to soak in and as the solution starts soaking in add more to the bucket until I get everything covered and then put the cover back on and kinda shack it a little then let it sit a bit and keep agitating it and keep letting it hit for a few days to keep letting it keep soaking in then after I’m happy with my soaking method pull out the items one at a time and either wring out the extra back in to the bucket and then somehow hang it about the buck to lit it drip back into the bucket and while before putting it on a hanger to hang up until it’s dry and ready to wear. Do you think my proposed method to soak and treat might work out ?

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