Strip down your switch, and buy an oven cleaner (like ''fornet'' which I use). It is a foam in a spray can. Apply some on the ''greasy'' surface, wait for 5 minutes and wipe it. I use pieces of foam to do it,from a sheet 1mx1m which I buy for that reason. Apply another coat and do the same again. After 4-5 times the part will be completely ''grease'' free. Since it is a small part normally it doesn't need to be repainted unless you have scratched it. If we were talking about the centre console things would be different. Bear in mind that the ''greasier'' the part is the easier you will clean it. So it is a good idea to heat it before you put the spray on it. Another alternative of painting is ''wrapping''. I suppose you have seen cars with 3M wrapping. 3M also has products for applications on smaller items. They come in every colour and texture. They even have some with metallic not only looks but ''feel'' as well. You can see many videos in youtube. If you see the result it is truly unbelievable.