Piano caseworks are finished in several different ways. Modern pianos often have a black polyester finish or another synthetic finish. These are very durable, but they still need to be looked after with care. The best thing to do is simply use a wax impregnated duster. Older pianos are often “French polished,” which is a process by which many layers of fine polish are built up and cut back to produce a very shiny finish. Some cheaper old pianos are brush polished and veneered or simply scumbled. Some rebuilt older pianos are spray polished with French polish or another synthetic finish such as a lacquer. These old pianos do not take kindly to any kind of spray-on furniture polish which contains silicone (most do). A beeswax polish is the best thing to use, as this will bring out the shine of the piano.