This troublesome thing, in theory, alcohol and organic solvents can remove the handwriting of the signature pen on it. But many table tennis balls are celluloid. This kind of table tennis consists of two halves, but this material may dissolve in alcohol. You can see if your table tennis is like this. If so, try acetone. If not, you should be more careful. If it is a seamless table tennis, the material of this table tennis is unknown. You can try.