One, you can use transparent glue, and it is the kind of wide sticky good. After gently sticking, the sweater will not be easy to shed wool again, even if it falls off again, it will only fall off a little. The first thing you can do is to dissolve a tablespoon of starch in half a basin of cool water, put the wool sweater in the starch solution and take it out, don't wring it, drain the water and put it in water with a small amount of washing powder, soak it for 5 minutes and rinse it, then put it in a net pocket and hang it up to drain, the wool sweater will not love to shed. Three, first wet the clothes with cool water, then mix the laundry detergent or professional wool sweater detergent with water at about 30 degrees Celsius, mix the two, soak for about 10 minutes, gently, rub more time in the more dirty places, rinse clean, wring out, dry with a good weight-bearing hangers, do not expose to the sun. After it is dry, then iron it flat, preferably with an iron.