Cashmere and wool are animal fibers and they respond differently to water than cotton. Hot water and agitation can shrink wool and felt cashmere — once the fibers lock, the damage is permanent.
Most wool sweaters, scarves, suits and coats are dry cleaned. Some lighter wool knits can be hand-washed cold and laid flat to dry; check the care label first.
Store wool and cashmere folded, not hung, so the shoulders do not stretch. In humid Florida summers, a breathable garment bag and a cool closet help keep moths and mildew at bay.