What sort of plastic part is it? Also, what kind of paint? Most paints can be safely removed from plastic by soaking in a lye based degreaser, such as Superclean or Purple Power. If it's laquer, soak it in 91% rubbig alcohol. If it's etched any, you might be able to bring it back by sanding it out using a polishing kit from the local hobby shop, which goes from 1200-12000 grit, then polishing with a good plastic polish.
