In short: clothes moth larvae eat wool, cashmere, silk and feathers, not the moths you see. Wash before storing, keep natural fibres in sealed Tyvek bags, monitor with a pheromone trap in the room, treat the empty wardrobe rather than the clothes, and check monthly. Cedar and lavender are pleasant but not a control.
If you have ever pulled out a beloved cashmere jumper and found it lace-trimmed in places it shouldn't be, you know the feeling. Moth damage is heartbreaking — and almost always preventable. The reassuring part is that the same techniques museums use to protect priceless tapestries work just as well in a domestic wardrobe.
What you'll need
- Knitwear Storage Bag — breathable, pest-proof storage for vulnerable knits
- Acid-free tissue paper — to layer between folded pieces
- Constrain Moth Spray — the museum-grade residual spray for treating wardrobes and drawers
- Pheromone Moth Traps — for monitoring and breaking the moth lifecycle
- Tyvek Garment Bag — for hanging suits, coats and dresses you want to protect
- Natural-bristle clothes brush — for regular brushing, the single most effective preventative habit
What you're actually dealing with
The fluttering little creatures you occasionally see aren't the problem. The adult clothes moth doesn't even have working mouthparts — it can't eat fabric. The damage is done by its larvae, which hatch from eggs laid on natural fibres and chew through wool, cashmere, silk, fur, and felt to reach the keratin proteins inside. They are tiny, pale, and very good at hiding.
Two species cause almost all UK damage: the common clothes moth (Tineola bisselliella), which leaves irregular holes, and the case-bearing clothes moth (Tinea pellionella), which builds a small silk case around itself as it eats. Both favour undisturbed dark corners and unwashed fabric.
Why your wardrobe is the perfect home for them
Modern centrally-heated houses are essentially year-round breeding grounds. Moths used to die back in winter; now they reproduce all twelve months. Add to that the fact that we tend to leave knitwear and woollens untouched for months, and you have ideal conditions: warmth, dark, food, and zero disturbance.
The single biggest invitation is invisible. Body oils, perspiration, food traces, and skin cells coat your clothes after every wear, even when they look clean. Moths don't lay eggs on truly clean fabric — they lay them on the parts that smell like dinner.
The conservator's approach: integrated pest management
Museums don't try to spray everything in sight. They use integrated pest management, or IPM — a sensible four-step rhythm: monitor, identify, treat in a targeted way, and prevent. The same method works beautifully at home, and it uses far less chemistry than the average mothball-and-hope strategy.
1. Monitor
You can't fix what you can't see. Place a couple of pheromone moth traps in the room where your wardrobe lives — not inside the wardrobe itself. The trap uses a synthetic version of the female clothes moth's mating scent to lure adult males onto a sticky pad, so putting it inside the wardrobe would actively draw moths into the very space you are trying to protect. The right places are quiet, dark, and undisturbed: behind the bed against the skirting, on top of a tall cupboard, underneath a chest of drawers, or in a corner behind furniture. Conservation entomologists recommend around two traps per average bedroom, and up to four in larger rooms.
Check them once a month and replace every twelve weeks, as the lure loses potency after that. If the trap stays empty, all is well. If you find anything stuck to it, you know it is time to act.
2. Identify the source
If a trap catches a moth, the next job is finding where they are breeding. Look for small irregular holes, pale wormlike larvae or tiny silk cases, fine sandy droppings (called frass), or felted patches in undisturbed corners. Pay particular attention to under-collars, cuffs, and the seams of folded jumpers. Check rugs, the felt under furniture, and any animal-fibre throws.
3. Treat in a targeted way
Once you have found the source, take everything out of the affected wardrobe or drawer. Clean any infested items by washing at 60°C (if the care label allows), dry cleaning, or sealing in a freezer bag and freezing at −18°C for at least 72 hours. This kills every life stage — eggs, larvae, and adults.
Then treat the storage area itself. Vacuum thoroughly, including the corners and skirting boards, and empty the vacuum outside immediately. Spray empty drawers, shelves, and the inside of the wardrobe with Constrain Moth Spray — a water-based insecticide developed for conservation environments. It is odourless when dry, non-staining, and gives residual protection for months; follow the label. Let it dry completely before returning your clothes.
Crucially: spray the storage area, not the fabric. The point is to leave a residual barrier where moths land.
4. Prevent
Once you are clear, the goal is to stay that way. Three habits keep moths out for good:
- Clean before storing. Always. Even clean-looking knitwear should be washed before going away for the season.
- Use proper bags. Breathable Tyvek knitwear bags keep pests out without trapping moisture. Plastic bags do the opposite.
- Keep monitoring. A pheromone trap placed in the room year-round (never inside the wardrobe) is the cheapest insurance you will ever buy.
Cashmere and silk: the most vulnerable fabrics
Anything containing animal protein is at risk: cashmere, wool, alpaca, mohair, silk, fur, and feathers. Cotton and synthetics are safe — but they can still harbour eggs that move on to nearby vulnerable items. So if you have a moth problem, treat the whole wardrobe, not just the woollens.
Silk is sometimes overlooked. It is protein-based and absolutely on the moth menu, especially if it has been worn close to the skin. Silk blouses, scarves, and lingerie need the same monitoring and clean-before-storing discipline as your cashmere.
What about mothballs, cedar and lavender?
Traditional naphthalene mothballs are no longer sold in the UK, and were never pleasant: the modern replacements smell strongly and can leave a residue in fibres. Cedar smells nicer but loses its aromatic oil within weeks, and only ever affected newly-hatched larvae in the first place. Lavender sachets are pleasant but largely decorative. None of them compare to a properly placed pheromone trap and a treated storage environment.
Frequently asked questions
How quickly can moths damage a jumper?
Larvae feed for several weeks before pupating. A small infestation can cause visible holes in a few months — but if you catch it with a pheromone trap early, you will usually spot it long before any damage is done.
Can I just freeze infested clothes?
Yes. Seal them in a bag (to stop condensation when you take them out), freeze at −18°C for at least 72 hours, thaw, then refreeze for another 72. This is the cleanest way to deal with anything you can't wash hot.
Are clothes moths dangerous to humans or pets?
No — they don't bite or sting, and they don't carry disease. The damage is purely to your wardrobe, which is bad enough.
Can I use Constrain in a home with children and pets?
Constrain is authorised by the HSE for indoor use (authorisation number 10297). Use it as the label directs: spray the empty wardrobe, drawer or storage space — never garments — keep children and pets out of the room while you spray and until surfaces are dry, and store the bottle out of their reach. It is odourless and non-staining once dry.
Catch them early, store things properly, and your knitwear will outlive most of your other possessions.
