1. If the sweater sleeves are long and want to be shorter, we can't just cut the sweater sleeves. Instead, first pick out a thread on the sleeve of the sweater and then cut it out. Then we can completely disassemble the sleeves and cuffs of the sweater along this line.

2. Then we need to put the complete cuff aside for use, and then shorten the thread on the sleeve.

3. After the sleeves are disassembled to a certain length, we can sew the sleeves and cuffs together along the line holes on the edges of grapefruit and cuffs that are the same color as the sweater.

4. This can shorten the sleeves of the sweater without leaving any traces, but it should be noted that when we use this disassembly method, it is best to remember how many times a sleeve has been disassembled to avoid the situation that the sleeves on both sides are different in length.

5. After the sweater is replaced, immerse the sweater in water. You can gently lengthen the stitched part with both hands at the same time, and then rinse it to dry. When it is half dry, first open it by hand, straighten it, and iron it with an iron to restore its original size.