A: According to designer Suzan Azuma of Mai, known for its hip cashmere tees, avoid dry cleaning; chemicals may damage delicate fibers, so sweaters are never as soft again. I suggest:
1. Hand wash with baby shampoo (or a specifically all-natural cashmere wash like White + Warren's—kinder than Woolite). Use sparingly and dissolve completely in cool to lukewarm water. Press suds through the sweater gently (no twisting or wringing); soak three to five minutes; rinse. Dry flat on a towel, away from radiators and direct sun.
2. Pills aren't a sign of cheap cashmere but the result of ordinary friction. Comb them out with a boar-bristle brush, mow them down with a battery-powered sweater shaver, or smooth them with the Sweater Stone, which does for pill-ridden knits what pumice stones do for rough skin.
3. Store items in separate bags so that if one is infested with moths—lured by perfumes and oils trapped in fibers—you won't lose the entire collection.