First, completely immerse the sweater in warm water at 30℃-50℃, or steam it in a pot for 20 minutes, so that it can slowly recover its shape until it basically recovers, and then put it in cold water for setting.

Second, help with a steam iron. Put the steam iron about two centimeters above the clothes with one hand, let the steam soften the fibers, and then shape the sweater with the other hand. In this way, when two hands are used together, the sweater will return to the original state of tighter fibers.

Third, when drying the sweater, in order to avoid the sweater getting bigger and longer, it is best to spread the sweater flat and dry it, or spread the umbrella out and dry it directly on it.