I have never used evaporust (nor polident), but does it clean as well as remove rust? For metal feet you can clean them with most water based soaps and detergents, I have even had them in hot water and white wash powder for clothes (exceptionally grimy case). If they soak for a while, then rinse and dry them they should not get damaged. Nickle will not rust, neither will chrome but those bluish metal parts can, so don't every put them though the dish washer or let them soak for a very long time. Unless it's very acidic I don't think polydent should do any harm at least.