Things You'll Need
3 bath towels
If you bought a wool sweater that is too large or if your sweater stretched out of shape, you can shrink it back to size in the washing machine. The process of shrinking wool is called felting. When you felt a wool sweater, the agitation and hot water of the wash cycle cause the fibers to bind together. When the fibers bind, the sweater shrinks. The process of felting requires you to keep a close eye on the wash cycle.
Put the unfolded wool sweater inside a pillowcase. Close the opening of the pillowcase by wrapping a rubber band around it several times.
Set the washing machine for a hot wash on the gentle cycle. Add a capful of wool wash as the machine fills.
Add two old bath towels to the wash. The friction provided by the towels will help the sweater shrink.
Allow the machine to run without going through the spin cycle. Open the machine and the pillowcase and check the sweater every five minutes. A felted sweater will start to become slightly fuzzy. If the sweater becomes too fuzzy or the stitches start to lose their definition, take the sweater out of the machine.
Rinse the sweater in a sink of cold water. Going from hot to cold water shocks the fibers, which completes the shrinkage. Remove the sweater from the sink when you're rinsed out all the suds. Roll it in another bath towel like a jelly roll to remove excess water. Lay the sweater flat to dry.
A sweater that is a wool blend will not felt. Only 100-percent wool can be felted.