Locate and read the garment-care label first. Some experts recommend dry-cleaning all wool unless the label tells you it’s washable.
If it reads “Hand Wash” or “Washable,” immerse it in warm water with a mild detergent and let it soak for several minutes. Swish wool gently and rinse, making sure all suds are removed. Wool should not be wrung out or twisted. To dry, roll wool garments into a terry-cloth towel, and then gently twist the towel. Lay flat to complete drying.
The only wool garments that may be laundered include the words “Machine Washable" on the care label. Follow all other label instructions for proper machine-washing procedures. Don’t tumble dry any wool garment unless the label says this is OK.
Don’t use chlorine bleach, strong alkaline cleaners or enzyme digesters on wool because they will damage or destroy wool fibers.
To remove wrinkles, don’t use an iron. Hang the garment in a steamy bathroom to relax wrinkles away.
Additional reference:
Don Aslett, The Cleaning Encyclopedia: Your A to Z Illustrated Guide to Cleaning Like the Pros