1. Check the damage of the cotton cover. If it is a hole or wear, it can be repaired with a sewing machine.

2. If there are stains on the surface of the cotton cover, it can be cleaned with detergent and then wiped clean with a wet cloth;

3. If the surface of the cotton sleeve is worn, it can be polished by a polishing machine to make the surface smooth;

4. If there are creases on the surface of the cotton cover, you can iron it with an iron to make its surface smooth.