Well, theoretically, any metal polish should make the plating look better, but remember, this is something someone is going to be putting on their mouth, so you might want to think twice about any toxic cleaning agents. Same with the red paint on the sides. Tell Arkie that I envy him for having an old harmonica that still plays. The first one I bought (mid-'60's)lasted for years. Today, I'm lucky if I get ten hours playing time out of them. Instruments are a bit like people, it's hard to make the really old ones look young. In my case, it would take a miracle.