1. Do not use a washing machine.
The friction from your washing machine's cleaning cycle will felt wool. The heat and soap shrink the garment and turn it from a soft, woven texture to a harder material – felt.
2. Soak in cold water
Dissolve a gentle cleaner in water first, to prevent it from reacting with the wet wool. Soak the sweater in cold water for 5-10 minutes before washing. This technique will prevent the wool from shrinking.
3. Gently squeeze suds through
Move the water and the detergent through the fabric. Swish the sweater around in cool, sudsy water until it is completely wet. After a few minutes of soaking and swirling, remove the sweater from the basin. Gently roll the sweater into a ball and squeeze out the excess water without wringing, rubbing or twisting the sweater. Wool tends to stretch easily and lose shape, so practice care when removing excess water.
4. Remove excess moisture with a towel, never wring or hang-dry, since wet wool stretches easily.
5. Dry the sweater flat
Now that your sweater is clean, all you need to do to dry is lay it flat in its natural shape. It can take days for wet wool to dry. Avoid drying the sweater in direct heat or sunshine.