Washing
By hand, in cool water, with a wool detergent or a little mild shampoo.
Press the water out against the side of the basin; never wring it. A knit holds its shape because the loops lie straight, and twisting takes them out of line. Rinse until the water runs clear. Wash it more often than you think you should, in the sense that cashmere is a fibre that likes water and a sweater worn against the skin is better for it. Dry cleaning is not necessary, and the solvents dull the hand over years.