To remove old, warn, dried on vinyl anti skid decals and strips, first soften them with the heat from a hair dryer or heat gun. Remove glue residue with rubbing alcohol or minerals spirits. Both are generally safe to use on all types of bath fixtures. They also can be used to remove glue residue from labels that are usually found on new tubs. Unless working on a metal tub, avoid the use of strong solvents like lacquer thinner. Metal tubs can withstand strong solvents. But some acids can etch the bottom. In fact, acids are sold to etch the bottoms to make them safer from slip accidents. However, etching the top surface of enamel shortens the life of the tub.