Good cashmere is one of the few genuine luxuries that rewards you for years — if you do not destroy it in the wash first. Learning the top 6 rules for washing cashmere at home is the difference between a jumper that softens and improves with age and a felted, shrunken thing that fits the dog. None of it is difficult; it is mostly a matter of resisting the instincts you have from washing everything else.
Cashmere is the fine undercoat of the cashmere goat, combed rather than sheared and prized precisely because the fibres are so fine and soft. Like all wool it is a protein fibre covered in microscopic scales, and that structure is both the source of its warmth and the reason it is so easy to ruin. Understand that one fact and the rules more or less write themselves; ignore it and you will felt a jumper the first time you get impatient at the sink.
Before you begin: what actually damages cashmere
Three things ruin knitwear, and they usually happen together: heat, agitation and the wrong detergent. Heat and movement make those tiny scales open and interlock, a process called felting that is irreversible — that is literally how felt is made on purpose. Biological detergents add a third insult, because their enzymes are designed to break down protein stains and cannot tell your dinner from your jumper. Every rule below is really just a way of avoiding one of those three. Always check the care label first; the rules here are the sensible default, not a licence to ignore what the maker tells you.
1. Hand-wash in cool water
Fill a clean basin with cool or lukewarm water — think comfortable, never warm to the hand. Turn the jumper inside out to protect the outer face, submerge it fully and leave it be. The single most common way people shrink cashmere is a hot wash, because heat is what encourages the fibres to felt.
Why it matters: keep the temperature down and you have removed half of the felting equation before you have even added detergent.
2. Use a gentle, wool-safe detergent
Reach for a detergent made specifically for wool and delicates, which will be pH-neutral and free of the enzymes and optical brighteners found in everyday powders. If you have none, a small squeeze of mild baby shampoo is a perfectly good stand-in. Use a little; excess detergent is hard to rinse out and leaves the fibre stiff.
Why it matters: ordinary biological detergents contain enzymes that digest protein fibres, quietly weakening the wool with every wash.
3. Soak and press, do not scrub or wring
Let the jumper soak for around ten minutes, then gently press it under the water with your palms to move the suds through. Do not rub stains, scrub the fabric against itself or twist it. If there is a mark, dab it gently rather than attacking it.
Why it matters: agitation is the other half of felting. A patient soak lifts body oils and grime without matting the surface into a dense, hard finish.
4. Rinse, then press the water out
Drain the basin and refill with clean cool water to rinse, repeating until the water runs clear of suds. Then, crucially, press the water out — cup the garment and squeeze gently against the side of the basin. Never lift a sopping jumper by the shoulders, because the weight of the water will drag it out of shape.
Why it matters: a wet knit is heavy and structurally vulnerable, and how you handle it in this minute decides whether the sleeves stay the length you bought them.
5. Dry flat, never on a hanger
Lay the damp jumper on a clean, dry towel, roll the towel up like a Swiss roll to blot out more moisture, then unroll and lay the jumper flat on a fresh towel or a mesh drying rack. Pat and coax it back to its proper shape while damp, and leave it somewhere airy but out of direct sun and away from radiators.
Why it matters: hang wet knitwear and gravity does slow, permanent damage, stretching the body long and pulling the shoulders into points. Drying flat is the whole reason your jumper keeps its shape.
6. De-pill and store folded with cedar
Once dry, tidy any little bobbles with a cashmere comb or de-pilling stone — pilling is caused by friction where the garment rubs, such as under the arms and where a bag strap sits, and is a normal part of wear rather than a sign of poor quality. In fact a good jumper will pill less over time as the loose surface fibres are gently worn away. For storage, always fold cashmere and lay it in a drawer or on a shelf rather than hanging it, and keep clothes moths at bay with cedar blocks or lavender sachets instead of acrid mothballs.
Why it matters: hanging distorts the shape even when dry, and moth larvae treat an unprotected cashmere jumper as a free lunch.
The Sixated take
Washing cashmere well is genuinely easy once you accept that everything you do to a cotton T-shirt is wrong here: cool not hot, press not scrub, flat not hung. Do that and a good jumper only gets better, blooming softer with each gentle wash. If a piece is heavily tailored, structured or you are simply nervous, the occasional trip to a trusted dry-cleaner is a reasonable insurance policy — but for the everyday jumper, ten minutes at the basin is all it asks. Treat it as part of building a wardrobe that lasts, the same instinct behind good capsule-wardrobe basics. None of this is medical or miraculous; it is just respect for a fibre that repays it.