Finally, Some Good Information about Those Nasty Wool-Eating Clothes Moths


moth hole in pantsClassic moth damage on wool fabric


Can you tell I hold a grudge here?  Hmm.  Well, let’s get down to it.  There are a lot of confusing “facts” and misinformation about clothes moths out there.  I’ve developed a system for dealing with them that works well for me, but I still wanted to know, from a scientific perspective, what actually kills them?  What temperatures can they tolerate?  What about water, can you drown moth eggs? Etc.  Some of these questions remain unanswered, and I’d still like to team up with an entomologist some day and nail down some specifics.  BUT (this is a big but) not long ago I stumbled on this post at Juniper Moon Farm.  They are doing some great stuff over there, and this was no exception.  The author, Lisa Stockebrand, lays out some specific advice which I heartily agree with: cleaning is the best response to finding moths in your wool, and you can kill all stages of them with heat or by freezing.

After I read this, I told Bryan about it, and how, even though of course I’d like it if our house was 100% moth-free (it’s not—they were here when we moved in—and it won’t be until all the old carpet is gone, all the baseboards are removed and cleaned behind, etc.) and of course I’m bummed that they have done damage in the past, at this point I’d rather have a system that works for dealing with them.  Sure, it’d be great to have a completely moth-free home, but as soon as one of my knitting buddies accidentally brings over an infested ball of yarn, it’s not moth-free any more, and so I would stick with my system even if I did think we were free and clear.

Less than a week after this discussion, I took a bunch of my felt samples to a small event, where they were displayed right next to an item which had clear moth damage, cocoons on it, etc.  So I had a bunch of felt to treat when I got home, and that got me thinking that now is as good a time as any to let you all know what I know about wool moths so far.


They Do Exist

Unfortunately clothes moths are alive and well in the 21st century.  I guess people who have never heard of them grew up in the age of acrylic (actually worse than moths in my opinion).  Those folks definitely have not cleaned out the houses of older relatives who worked with wool!

Although the moths themselves are definitely up to no good, scouting around for your most precious garments to lay their eggs on, it’s the larvae that actually eat the wool.  They also eat fur, and mixed fibers containing wool or other animal fibers, and can survive on dust bunnies alone, especially if said dust bunnies contain pet hair.  Supposedly they also eat silk, although I have never seen one on a pure silk garment.  There are two common kinds of wool moths (at least here in the US) and they both look pretty much alike: usually tiny (less than a centimeter long) shiny golden moths with tattered-looking edges to the wings, and red eyes.  The eggs are incredibly tiny, and the larvae, when they first hatch, are practically transparent, and thinner around than a sewing thread.

How, pray tell, do I know that last part you may ask?  Well, one time, years ago, we came back from a long trip and there were quite a few moths flying around the house (the woolens were packed away but I was still pretty mad).  After crushing the first couple dozen I could catch, I decided to capture a few and leave them in jar to see what would happen, in the spirit of “know your enemy.”  Probably the most interesting and disturbing thing I found out was just how practically invisible the larvae are when they first hatch.  I could easily give an item a thorough inspection and not see one at all.  Probably the second most interesting thing I found out was that yes, a couple of days in my freezer does seem to kill them.


moth and larvaIf you click on the links at the bottom of Lisa’s post, some of them have photos of actual moths.



They Can’t Eat It if You’re Using It

This is the most important thing I’m going to write in this post, so take note: moths are not a threat to woolens you’re using, only those you’re storing.  I have lots of wool clothes, and I just love them.  I wear them all winter long, without worrying a bit that little things with wings will attack them.  That’s because if you’re wearing something, it’s out and about, it’s in the light (which clothes moths don’t like), it’s brushing up against other things, it’s being cleaned and then worn again … in other words, even if a moth did lay eggs on it, chances are very high the eggs would be destroyed or brushed off before they hatched.


Store it Well if You’re Not Using It

When the weather warms up, I wash my woolens, bit by bit usually, and store them for the summer, in a suitcase in the garage.  Dirty clothes are more likely to attract moths, not to mention it’s not good for the fabric to let stains and oils just sit there.  In a weird way I kind of love doing this, and especially love opening up the suitcase in the fall when it’s full of wonderful things for winter.  I hand wash everything except a large rug and my not-me-made coat, which go to the cleaners.

I also use plastic tubs to store yarn and fabric scraps, and some plastic bags inside those as well.  When I worked at a museum, I learned that airtight plastic bags are not really a good choice for long term storage of textiles, you want some airflow, otherwise the air in the bag will become different enough from the air outside that just taking the textile out can damage or destroy it.  But while plastic bags aren’t the best choice for preserving your grandmother’s wedding dress, they should be fine for keeping your yarn stash organized, as long as you open them now and then.  In my mind, the absolutely ideal container for wool storage is one that seals tight to moths but not to air, which is why I use a suitcase (with a tight closing zipper) for summer storage.  Whatever you use, make sure it closes tight enough to keep a little moth from wandering in.  Moths can eat through paper bags and cotton to get what they want, but they only will if what’s in there really grabs their attention.

Cold definitely slows moths down, and may kill them if the conditions are right.  I’ve had good results storing wool for felting, and materials for making my cashmere hats, in big plastic tubs that stay on my back porch year round.  About half the year, it’s pretty cold out there, and usually freezes at night.  I keep my knitting yarn bin out there for part of the winter too.  The rest of the time it stays in the garage.  I’ve also had good results storing wool yarn and fabric scraps that I’m not going to use right away in the garage, either in plastic tubs or in a cardboard box with the seams taped shut.  Again: treat/clean things, then store them.


Two Mistakes You Don’t Have to Make

As my friend Tom says, “You don’t have to make this mistake, I have already made it for you.”

1.  Don’t bring home a new wool rug without having it cleaned, especially if it’s imported and/or has been stored for a while.  Seriously, take it straight to the cleaners when you buy it, then bring it home.  Same thing with any old yarn or sweaters someone donates to you.  Treat them (see below), then wash them, then use them.

2.  Don’t assume that something which has been hanging in your closet for a while is moth-free, and put it away.  Treat it and/or clean it every time before you store it.


How to Kill Clothes Moths

If you find moths in your house, I can’t recommend a better strategy than what’s in Lisa’s article, which I linked to at the top.

It appears, from the incident with the jar of moths as well as other anecdotal evidence, that the ordinary freezer attached to my fridge is enough to kill moths, although that has not been scientifically proven for all stages of moth life.  There was also an incident in which a moth attack got started in a storage bin (see 2. above) but then halted, and the larvae appeared dead when I found them.  I have a theory that, while the temperature was not low enough to kill the eggs, at some point it did freeze hard enough to kill the larvae.  This was in the garage.  This is just a theory.

When I brought home my felt samples that were possibly exposed to moth eggs, I decided to try treating them with heat, since I could cycle through everything I needed to treat in a day, rather than over weeks if I used the freezer.  Lisa recommends temps over 120° F for at least 30 minutes.  Washing in water over that temp also works, but I decided I’d rather keep the wool dry so that I could store it right away.  I’ve also steamed small amounts of yarn above boiling water, the way you would a vegetable, and that should work as well, as long as the heat penetrates to the middle of whatever you’re steaming.

I did put a pan of hot water on the lowest oven rack, so that the heat I was exposing the wool to wouldn’t be completely dry.  The lowest temperature my oven will set at is 170° F, and I went for 200° just for good measure.  I put an old towel directly on the middle oven rack, and put the wool items, not too many at a time so that the heat had a chance to penetrate, on top of that, and set the timer for 40 minutes before taking them out and putting in the next batch. At the end, the only thing that showed any signs of scorching was where the towel touched the sides of the oven, so I suggest folding your towel so that it doesn’t touch the oven walls.  I keep a baking stone on the top rack of my oven, and I left it there to hold heat.  If you wanted to, I think you could also do two racks of wool at a time, as long as you allow time for the oven to heat back up after you load everything in.

wool in oven When one batch was done, I put it somewhere clean, and while the last batch was heating, I wiped out the plastic storage bin I keep the felt samples in with a damp cloth, and let it dry in the sun.  The cleaning part always seems like no fun at first, but once I’m doing it, it occurs to me that it was high time anyway, and it feels good in a spring-cleaning kind of way.  When I put the samples back in the bin I felt confident that they were good to go.

This is in Lisa’s article, but I’d like to emphasize it: please please do not use mothballs.  This is another thing I learned from working at the museum: mothballs are truly horrible, they are toxic to all kinds of creatures, including me.  I’m pretty sure I left a few brain cells behind while going through their collection of furs.


And Finally, Spiders

A thought about spiders: another time we returned from our summer journeys to find that moths had hatched in the house, but this time most of them were in a spider web in the studio.  Ever since then, I have let spiders be in the house (except if they’re in the sink, the bathtub, or building a web somewhere very inconvenient) instead of trying to relocate them outside.  It started me thinking that the spiders, being so much smaller than I am, and adapted to eat bugs, and hungry, might be much much better than I was at finding moth larvae under the edges of the carpet, etc.

I can’t say for sure what difference leaving the spiders has made, but I will say that over the past few years, all these strategies combined have meant that I only see a couple of moths a year (and, um, SQUASH them) and more importantly, I’ve managed to keep all the things I care about from getting munched on.

There’s a lot here (phew!), but I still promise to update/post more as I learn more!


12 thoughts on “Finally, Some Good Information about Those Nasty Wool-Eating Clothes Moths

  1. Pingback: Me-Knit Blue Sweater with Lace | Stale Bread into French Toast

  2. Thank you. I had a most infestation recently. They got my stash, my handknit lace shawls, and my husband’s stack of sweaters. I cleaned the house thoroughly and all of these things have been in the freezer until I get up the energy to deal with them. I am a little nervous about sticking them in the oven but plan on trying your technique!

    • Oh no! If they’ve been in the freezer for quite a while, the moths are probably dead already. You could just get out a few things at a time, repair and clean them, and then store them carefully. Of course, you can put them through the oven as well to be safe. Good luck!

  3. Hi Tasha. Thanks so much for this post, and for your link to Lisa’s helpful article. I’ve just discovered moths on a wool carpet that was rolled up in a closet upstairs. Before I found the moths the carpet was moved to the living room. I have a new baby and have to direct my cleaning time to the highest priority items to try to control the moths. From what I’ve read, I need to treat / clean all fabric items that were in the closet with the carpet, even of there’s no sign of larvae on the item, just to be safe, do you agree? Do I also have to throw out or clean non fabric items, like open boxes containing gift bags and wrapping paper? What about a hat box and hats it contained? How do I clean those? What do you recommend wiping the inside of the closet with? The closet door was often left open – do I have to wash clean cotton baby clothes that were sitting right in front of the closet in laundry baskets? Any thoughts re what I need to do / clean in the living room where the carpet sat for a week before I noticed the moths? I’ve seen a flying moth in the living room downstairs, and another in the nursery on a baby towel hanging in the back of the nursery door. So sorry for all the questions. The room the carpet was in is supposed to be the nursery and am just so overwhelmed trying to figure our how to tackle this! Any advice would be a huge help! Thank you.

    • Hi Sarah, sorry to hear about your moth problem! So, first I would get the carpet out of the house if you haven’t already. Wrap it in plastic if you have a some big enough, and take it to the cleaners. If it’s still freezing at night where you live, you could leave it somewhere outside for a couple of nights first to kill any live moths/larvae.

      I would clean all fabric that was in the closet, starting with anything wool. I would also wash non-wool fabrics that have been in the closet, just in case they have eggs on them. Moths can’t eat plant fibers like cotton, but I’ve seen them perch on cotton towels etc. at my house when they couldn’t find any wool, and probably lay eggs there. I’d imagine your piles of baby clothes will get washed/worn pretty quickly, in which case I wouldn’t worry about giving them an extra wash, unless they’re going to be stored for a while.

      For the rest of the items and the closet/living room, you shouldn’t need to wipe things down, just vacuum and dust as thoroughly as you can, and send any other wool carpets to be cleaned as well. Anything in a sealed container should be safe. I’ve had good luck with wool hats by vacuuming them for dust and any possible moths, and storing clean in something with a tight-fitting lid. If you find moths in a box with wool hats, I would freeze, heat treat or send the hats to be professionally cleaned. As far as things like paper, I would just go through them and make sure there aren’t any moths currently hiding there. Any larvae that hatch in a bag of paper shouldn’t survive because they won’t have the right proteins to eat.

      Be extra careful with other wool items in your house, like sweaters, especially if you’re storing them for the summer, clean every one before putting it away, and make sure the storage box is moth-proof. Since you’re going to need to do this in stages, you might consider putting anything wool that you’re not currently wearing in a freezer (or a bin outside if it’s cold) and then getting things out and washing them a few at a time as you have time (or send the whole bunch out to be cleaned).

      I just finished reading The Intentional Spinner by Judith MacKenzie McCuin, which has a section on the back about moths and mice, including some good suggestions on chemical treatments if you decide you need to go that route, and I found her thoughts very complete and helpful.

      I hope that helps! Good luck!

  4. I have been battling clothes moths since March. I thought I had gotten rid of them but I found them again last month. The first time around I had put all the clothes in the laundry at 60 degrees but this time around I am trying the oven method. I bake each batch of clothes at 70C for an hour or two and I must say it is a heck of a lot easier than washing everything and waiting for it to dry. I really really hope that it works because I am so sick of those disgusting larvae…

    • Hi Ariana, yeah it’s totally gross and disheartening when you find the larvae! Keep in mind that they could be hiding somewhere (like under the baseboards, eating pet hair, etc.) and could come back again. The best advice I can give you is to make sure you clean the area as thoroughly as you can, as well as the clothes.
      I wouldn’t say that I’ve reached peace with the moths, but I have accepted that they live pretty much everywhere. Since I have friends who also do fiber arts, and so wool and textiles coming in and out of the house, I do think it’s better to expect that moths could and probably will show up again, and prepare accordingly. The good news is that since I started being very careful about how things are stored, nothing has been eaten, even though I’ve seen moths in the house since. Good luck!

  5. i had moths get hand knits and yarn that was in 2 tight fitting bins, including an airlock bag inside one of the bins! I am beside myself. I wear something and immediately put it back in the bin.. can they really get into plastic bins???

    • Argh—how frustrating! They can’t eat through thick plastic, but they can crawl through the tiniest holes. Sometimes bins that look like the lid fits tightly actually have little fins of plastic that keep the lid from making contact with the top of the bin all the way around (in which case I choose a different bin for wool storage). Or they may have air holes made on purpose, often under the handle (which I usually cover with thick tape).
      The other possibility (unfortunately this has happened to me) is that something you thought was clean when it went into the bin actually had moth eggs on it already. Obviously you’ll need to treat everything that was in the bins when they were contaminated as if it has eggs before storing it again. The oven or steamer method is probably the best for yarn.
      When storing yarn or things you don’t need access to all the time, it may help to find a cold place to keep the bin, like the garage, shed, back deck etc. Moths move much slower in the cold, and if you live somewhere with cold winters, freezing temperatures can kill larvae and adults.
      If you have a bin that you’re moving garments in and out of during the winter, it’s still important to wash everything and clean out the bin before you store it over the summer, or for more than a week or so, just in case something made contact with moth eggs.
      I hope some of that helps!

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