In May of last year, Allison Wolf noticed a couple of small moths fluttering around her Brooklyn apartment. “I didn’t really think anything of it until I found frass all over the yarn in my crafts drawer.”
Frass, for the uninitiated, is a more quaint-sounding word for insect larvae excrement. This pellety substance is the evidence that moth larvae (aka caterpillars) leave behind after munching through your wardrobe, and it’s a telltale sign that you have a potentially very costly moth problem. The hungry caterpillars chowed down on Wolf’s hand-knit sweaters, too, snubbing the store-bought ones, and devoured her cats’ feathered toys.
In nature, moths feast on feathers in abandoned bird nests and the fur and skin of dead animals. “We’d be up to our eyeballs in feathers and fur if they didn’t exist,” says Mary Ballard, a textiles conservator at the Smithsonian Institution. Trapped in your home, they have no choice but to dine on some of your most expensive belongings: cashmere sweaters, fur coats, alpaca blankets, wool suits—anything with keratin.
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“Caterpillars love natural fibers, particularly with your body oil on them as a nice salad dressing,” says Elena Tartaglia, a moth expert and biology professor at Bergen Community College in New Jersey. “They love dark, undisturbed places, so your winter clothes stored in an attic or basem*nt is the perfect storm.” And while there technically isn’t a clothes moth season, a warmer, more humid summertime environment speeds up the moth life cycle—and the infestation.
Fortunately, there are a few simple strategies that don’t hurt your wallet or involve pesticides. Spoiler: Cedar and other natural repellents won’t do squat! Extremely cold and hot temperatures will. The key is to take the following steps at the first sign of trouble, whether it’s a pair of fluttering wings or a random, asymmetrical hole in a sweater.
Step 1: Inspect
Thoroughly check each of your garments for damage or signs of the larvae in bright sunlight or with a flashlight. “It’s not the moth that’s doing the damage, it’s the worm,” says Jennifer Brumfield, an entomologist at pest control company Western Pest Services. “You know a hole is moth-related when there’s also gritty fecal material and cocoon material,” which looks like fibrous tubes or spun webbing. You might also find larvae, which resemble small white caterpillars, or pinhead-sized cream-colored eggs.
If you find one moth or moth-riddled hole, don’t delay moving on to step two. “A single female moth will lay an average of 50 eggs, and then those babies will be having babies within months, and each of those babies will have more babies, and you see where this is going,” Brumfield says.
Check other common infestation areas, including your crafting drawer, rugs, the felted lining in the pianos, cracks and crevices in flooring, and any other place where hair, fur, and lint can collect.
Step 2: Treat
If the damage is not extreme and you want to have the garment repaired, brush off any of the eggs, larvae, frass, and casings, and throw them away in a sealed container, like a plastic zipper bag. You can then eliminate the moths in all life stages using the following methods:
Cleaning
Ballard says the heat and solvents used in dry cleaning will kill any remaining eggs and larvae. Alternatively, you can hand-wash delicate items with shampoo or a detergent for wool. Just don’t put knitted wool items in the washing machine, which is very likely to shrink them.
Freezing
This method can also destroy clothes moths and is especially useful for items that can’t be dry-cleaned, such as accessories, ornaments, and purses. Seal them in airtight bags and place them in the freezer for a week (72 hours if your freezer is colder than -20°F). The temperature must be lower than 20°F, Brumfield says. If not, or if you don’t leave the item in long enough, the caterpillars can just wake back up and continue their meal. Fabric fibers become brittle when frozen and can break, so let the items defrost fully before unbagging them.
Heating
Heat also works as long, as it’s over 120°F for at least 30minutes, Brumfield says. The hottest dryer setting will do the job. Place the item in dry and be mindful of what you toss in there: Ballard warns that heat and mechanical action can affect the texture of fine wool clothes.
Once you’ve cleaned your clothing it’s time to tackle your home. “The problem won’t go away if you don’t clean out the closet and get rid of the dust bunnies and other potential nesting zones,” Ballard says.
Use your vacuum cleaner’s hose and crevice tool to target any areas where hair, pet fur, and lint accumulate, including cracks and crevices in flooring, baseboards, shelves, drawers, closets, and chests. Before you start, vacuum up a handful of a natural desiccant, like baking powder, baking soda, baby powder, dry rice, or diatomaceous earth first. “Having that stuff spinning around in the vacuum bag or the canister will destroy any eggs you suck up like shrapnel,” Brumfield says.
Put the cleaned clothing back inyour closets and drawers only after you’ve thoroughly vacuumed them out.
Step 3: Protect
If you’ve had your clothes dry-cleaned, remove the plastic covering as soon as you get them home to avoid yellowing the fabrics. For seasonal storage, Ballard suggests wrapping the clean clothes in acid-free paper or turning your clothes inside out (so if it yellows, only the inside looks weird) and placing them in a tightly sealed plastic tote or vacuum-sealable bag.
As a preventive measure, place garments that you continue to wear in the dryer or freezer once or twice a month, just in case there are any small eggs on them. Shake them out or brush them before putting them back in a drawer or on a hanger.
Don’t bother with natural “moth repellents,” including cedar, lavender, cloves, vinegar, and black pepper. “I’ve dealt with many infestations in cedar closets,” Brumfield says, adding that these substances don’t deter moths. Ballard warns that cedar chests and the cedar oil in them are acidic and can damage wool sweaters and fine fabrics.
Mothballs work, but only because they’re a highly toxic chemical with noxious vapors that can harm all living creatures, including you, your children, and your pets. The only safe way to use them is to place them in an airtight container with your clothes, which will come out smelling like mothballs when winter rolls around again. “Just avoid them because there are all these nontoxic ways you can prevent infestation,” Tartaglia says. “Put your clothes away clean, either by freezing them, heating them in the dryer, or getting them dry cleaned. That’s really all it takes.”
Keeping a sticky pheromone trap in your closet can provide an early warning of future infestations. They only attract male moths, but if you spot one of those, there’s a good chance a female is nearby. Act quickly, and you can keep your clothing off the moth menu.
Perry Santanachote
As a multimedia content creator at Consumer Reports, Perry Santanachote covered a range of trends—from parasite cleanses to pickleball paddles. Perry was also a main producer of our Outside the Labs content, evaluating products in her tiny Manhattan apartment.