I have a phenolic black wwii Navy clock case with an unusual (to me) problem. I will post a couple of photos here. The case is phenolic plastic. However, it has a "rash" that looks like rust. In spots, this looks like it may penetrate the surface, and may be a brown phenolic material? It will not polish away with either Glayzit or Novus #2. Any suggestions as to how to remove this? Or is a coat of black paint in order? If so, lacquer or enamel? Thanks!!