How to Get Rid of Clothes Moths: The Moth You Can See Isn’t the One Eating Your Sweaters

Mid-November is when it happens. You pull the good merino out of the bin under the bed, hold it up to the window, and there it is: a little constellation of holes across the front, usually right where your collarbone sits. You saw a moth or two fluttering around the closet in September and didn’t think much of it. That moth was probably the least of your problems.

Most guides on how to get rid of clothes moths give you the same checklist of vacuuming, washing, cedar and traps, and none of it is wrong. What they skip is the biology that decides whether any of it works: the moth flying around your closet isn’t eating anything, the trap only catches half the population, and the holes cluster where they do for a reason you can fix in an afternoon.

The moth flying around your closet has already done its damage

Adult clothes moths don’t eat. According to the University of California’s Integrated Pest Management program, all the damage comes from the larvae, which can spend anywhere from 35 days to two and a half years feeding, depending on how warm your house is and how much food they have. A female lays an average of 40 to 50 eggs over two to three weeks and then dies. The larvae also avoid light, so they’re tucked into folds and seams where you won’t see them, while the adults you do see are mostly males drifting around looking for mates.

That’s why the classic sequence feels so unfair. You notice a moth in late summer, swat it, feel like you handled it, and then find the holes two months later when the weather finally turns. By the time you see a flier, the next generation may already be eating.

The problem isn’t limited to old country houses, either. When English Heritage ran Operation Clothes Moth, a citizen survey launched in 2017 that handed out about 4,500 traps across 42 English counties, participants caught 3,607 webbing clothes moths, an average of 17 per trap. Flats with shared walls were more likely to be hit than detached houses, which is a useful thing to know if you live in an apartment building.

Your pheromone trap is a smoke detector, not a fire extinguisher

The trap box doesn’t put this on the front, but Dr. Killigan’s says on its own product page that its traps “only attract mature males.” UC IPM says the same about clothes moth pheromone traps in general: the scent pulls males onto a sticky card. Trapped males can’t mate, so there’s some control value, but the egg-laying females aren’t the target.

So think of the trap as a smoke detector. It tells you moths are active and roughly where, which is useful. It won’t save a sweater that already has larvae in it.

The cost math makes the point. A six-pack of Dr. Killigan’s traps is $18.48 on sale (regular price $24.97), and the company recommends replacing them every three months. Run traps year-round as your main defense and you’re buying four packs a year, $73.92 at the sale price or $99.88 at full price. That’s real money for something that, by design, skips the females. A single trap in each closet as an early warning makes sense. A wall of traps as your whole strategy doesn’t.

How to get rid of clothes moths starts with storage, because the holes cluster on sweat stains

This is the gap most moth guides leave open, and it changes what you should do this weekend. Colorado State University Extension notes that clothes moth larvae need B vitamins and salts that are missing from completely clean wool. Perspiration and other soiling supply them, so attacks focus on the dirty patches. UC IPM puts it more bluntly: clothes moths prefer fabric with food, sweat or urine stains.

That explains the collarbone and armpit holes. It also explains why the sweater you wore once in March and folded away “because it wasn’t really dirty” is the one that got eaten. To a moth larva, a sweater worn once is a meal.

So the most important step in how to get rid of clothes moths happens before storage. Anything wool, cashmere, alpaca or silk goes away clean. UC IPM says laundering kills all life stages if the water is at least 120 degrees Fahrenheit for 20 to 30 minutes, which is fine for sturdy items but not for most knitwear, so for delicate pieces use a dry cleaner or the freezer.

The freezer method is free and works on anything that can’t take hot water. CSU Extension says temperatures below 0 degrees Fahrenheit “will almost always be lethal to insects following a 72-hour exposure.” Seal the sweater in a zip bag, press out as much air as you can, and leave it for three full days. CSU adds a detail that most how-to posts leave out: let the item sit at room temperature first, because insects cooled slowly can build up some freeze resistance. If your freezer runs warmer, UC IPM’s version is below 18 degrees for several days, so give it a week to be safe.

The math on one missed female is why you treat the whole drawer

It’s tempting to toss the one sweater with holes and move on. The numbers say otherwise.

Take UC IPM’s figure of 40 to 50 eggs per female and use the midpoint, 45. Assume roughly half of those hatch into females, so about 22. If each of those lays 45 eggs, you’re looking at 22 times 45, or 990 larvae in the second generation. UC IPM puts the full egg-to-egg cycle at four to six months, with about two generations a year in a heated home. One female who slipped into your sweater bin in May could, on paper, mean close to a thousand larvae feeding by the next cold snap.

Real life is messier than that, since not every egg hatches and not every larva survives. Still, the direction is clear. When you find damage, treat everything stored in the same bin or drawer, not just the item with holes. Freeze or clean it all, vacuum the drawer corners and closet floor edges where larvae hide from light, and only then put things back.

Cedar smells nice, but it’s working on borrowed time

Cedar blocks are the default fix, and the extension data is unkind to them. CSU says red cedar oils only kill larvae at high concentrations, don’t repel adults, and lose strength as the oils evaporate. One study it cites suggests cedar chests more than three years old are practically useless against larvae. UC IPM agrees that cedar oil kills only small larvae and fades after several years, and that a tightly built chest does more than the wood itself.

That last point is the useful one. What protects stored wool is a closed container moths can’t get into. A lidded plastic bin with clean, frozen-and-thawed sweaters inside beats an open shelf full of cedar balls. Mothballs do work in airtight containers, but UC IPM flags them as toxic around kids and pets, and they can soften plastic buttons and hangers, which is a lot of downside for a smell you’ll have to air out of every sweater.

If you’ve been knitting this season (our guide on starting with a hat instead of a scarf has the case for it), your handmade wool deserves the same treatment. And while you’re doing a winter wardrobe check, it’s a good time to give your boots the whole-panel salt stain fix too.

If you want to know how to get rid of clothes moths without paying for a year of trap refills, the routine is short. Use one trap per closet to tell you whether they’re active. Clean or freeze anything wool before it goes into storage, and never put away a sweater you’ve worn even once. Store it all in a container with a lid that seals. Do that this month while the sweaters are coming out anyway, and next November the bin under the bed should hold sweaters instead of surprises.