One thing worth remembering when caring for knitwear is that a little extra attention can make a real difference. A wool jumper does not need to be washed after every wear; often, airing it out and treating small stains promptly is enough. Before putting knitwear away for the season, check the care label, make sure the garment is completely dry and store it in a clean, dry place. These simple habits can help your favourite pieces stay comfortable and wearable for longer.
Late October is when the knitwear comes down from the top shelf. For many of us that means a moment of dread: a favourite cardigan that has gone fuzzy at the elbows, a jumper that came out of last winter’s wash a size smaller, or a neat little hole in the front of something cashmere that was perfect when it went into storage. None of these is bad luck. Each has a clear cause, and each is mostly preventable once you know how wool behaves.
This guide pulls together advice from the wool industry’s own testing body, a Scottish cashmere mill, and the conservators who protect historic textiles in England’s heritage collections. It covers the three problems that ruin most knitwear: shrinking, pilling and moths.
Why wool shrinks, and why it can’t be undone
Every wool fibre is covered in microscopic scales, a little like roof tiles. According to The Woolmark Company, heat and moisture make those scales lift, and then agitation, such as tumbling in a drum or rubbing by hand, makes them catch on the scales of neighbouring fibres in what it calls a “ratchet-like mechanism”. The fibres lock together, the fabric gets denser, and the garment shrinks. Woolmark is clear that this interlocking is irreversible, which is why no amount of tugging will bring a felted jumper back.
The practical takeaway is that shrinkage needs all three ingredients at once: warmth, water and movement. Take away any one of them and you are largely safe. That is also why some wool is sold as machine washable. Woolmark explains that these yarns are treated to remove or smooth the scales, reduce friction between fibres, or both. The most widely used method, known as Hercosett, combines a chlorine pre-treatment with a thin resin layer that bonds to the fibre. If your label says machine washable, it has almost certainly had a treatment like this, and you can trust it more than an untreated hand-knit.
How often to wash, and how to do it
The first good news is that you need to wash wool less than you think. Woolmark notes that wool naturally resists stains, odours and creases. Johnstons of Elgin suggests washing knitted cashmere after it has been worn three or four times, rather than after every outing. Between wears, airing a jumper over the back of a chair overnight does a lot of the work.
When it does need a wash, first read the care label. Then choose your method.
Hand washing is the gentlest option and the right one for anything labelled hand wash only, for most cashmere, and for hand-knits. Here is the routine, combining Woolmark’s guidance with the Johnstons care notes:
- Turn the garment inside out.
- Fill a clean basin with lukewarm water. Woolmark suggests about 30°C; Johnstons suggests 35°C for cashmere. Either way, it should feel barely warm on your wrist.
- Add a wool detergent or a cashmere shampoo. A mild, neutral detergent will do if you have nothing specific. Woolmark-approved products carry its symbol on the packet.
- Let the piece soak for around 10 minutes. Gently squeeze the suds through it rather than rubbing, which is the agitation you are trying to avoid.
- Rinse in lukewarm water, then again in cold. Johnstons stresses rinsing at the same temperature as the wash for cashmere, so avoid sudden jumps from warm to icy.
- Never wring or stretch. Press out the water, then roll the garment in a towel to lift out more moisture, as Permanent Style recommends.
Machine washing is fine for garments whose label allows it. Woolmark’s advice is to use the wool programme, which is usually a gentle action at 40°C, or a cold or delicates cycle if your machine has no wool setting. Turn the piece inside out or put it in a laundry bag; a pillowcase works in a pinch. If you are unsure whether a jumper is treated, hand wash it. The cost of guessing wrong is a garment you can’t rescue.
Woven wool and cashmere, such as scarves, stoles, coats and suits, is a different matter. Johnstons recommends dry cleaning woven cashmere, and asking the cleaner for the “F” method rather than PERC, a solvent several countries have banned. For small fresh marks, it suggests dabbing with a lightly damp cloth in cold water, or a little fizzy water, after testing on a hidden spot first.
Drying: flat, shaded and patient
Drying is where many careful washes go wrong. All of our sources agree on the basics: reshape the knit and lay it flat on a dry towel or a mesh rack, away from radiators and direct sun. Woolmark specifically says to flat-dry knitwear in the shade. Johnstons is blunt about the tumble dryer for cashmere: don’t. Hanging a wet jumper is also a mistake, because the weight of the water pulls it out of shape. Permanent Style adds a useful detail: don’t let the sleeves dangle over the edge of the rack, or they will stretch. A warm, airy room helps it dry before it can get musty.
Once dry, Johnstons suggests a light press with a cool iron if needed.
Pilling is normal, not a sign of a bad jumper
Those small bobbles are loose fibres that have worked their way to the surface and rubbed into tiny balls. Johnstons describes pilling as something that happens as fibres rub together during wear.
One surprising point from Permanent Style is that very fine cashmere can pill more, because finer cashmere tends to have longer fibres. Pilling on its own tells you little about quality. What matters is whether it settles. The same article suggests wearing a new jumper two or three times before its first wash, and then washing it regularly, to help the loose fibres shed.
To remove pills, Johnstons recommends a de-pilling comb or simply picking them off by hand. Lay the garment flat, hold the fabric taut, and use short, light strokes in one direction. Permanent Style also mentions an emery board as a cheap fix for small areas. Whatever tool you use, work on a clean, dry garment, and stop once the surface looks even. You are tidying, not sanding.
Moths: the larvae are the problem
The holes are not made by the little moths you see fluttering. English Heritage, which battles moths across its historic houses, explains that only the larvae damage materials. Adults of the common webbing clothes moth, Tineola bisselliella, are just 5–8 mm long. They avoid light, hide in dark corners, and lay eggs on wool, fur, feathers and skins. One generation usually takes a year, but in warm conditions there can be up to three.
English Heritage’s prevention tips are written for stately homes, but they translate neatly to a bedroom wardrobe:
- Store only clean clothes. Soiled textiles are attacked first, so wash or clean knitwear before putting it away for the season.
- Seal it up. Tightly sealed boxes or vacuum bags keep out moths, damp and dust. Johnstons suggests a drawer, box or breathable sealed bag with cedar balls for cashmere.
- Disturb things. Moths dislike disturbance, so shake hanging clothes at least once a month and check drawers and trunks.
- Vacuum the wardrobe. Regular vacuuming is described as the most effective measure. Use a crevice tool along shelf edges and the wardrobe floor, then empty the vacuum into a sealed bag in an outside bin.
- Check the hiding spots. Look in collar folds, armpits, lapels, pockets and turn-ups, where larvae like to tuck themselves away.
A word on lavender and cedar. English Heritage notes that lavender is a safer alternative to old mothball formulas, which are now banned or not recommended, but that it is not effective on larvae. Treat scented sachets as a pleasant extra, not a defence. Cleanliness, sealing and regular disturbance do the real work.
If you find moths already
Freezing is the conservator’s method. English Heritage says deep freezing is the best way to kill adults, eggs and larvae: seal the item in a plastic freezer bag and keep it at −18°C for at least two weeks. While items are in the freezer, vacuum and wipe out the drawer or wardrobe they came from, or the cycle will simply start again.
For a small hole in a good piece, a skilled repair is often worth the cost. Johnstons, for example, points to invisible mending through its Cashmere Circle service.
A ten-minute routine for the start of the season
As your knitwear comes out of storage, take each piece out in good light. Shake it, look along the seams and folds for webbing or holes, and freeze anything suspicious before it joins the rest of your clothes. Air the pieces that look fine for a day. Then, before it goes back into storage in spring, give everything a proper wash, dry it flat, and pack it clean into sealed boxes. Done twice a year, that small habit will keep a good jumper going for many winters.
Sources: The Woolmark Company (How to wash a wool sweater, Can I wash wool in the washing machine?, Machine-washable wool); Johnstons of Elgin, How to care for your fine fibres; English Heritage (Understanding clothes moths, Top tips for preventing clothes moth infestations); Permanent Style, How to stop sweaters pilling.
