Can you tell me how to clean white vinyl racing stripes on a black mustang? They look dingy with embedded dirt and water spots from rain. A simple wash doesn’t remove these stains. My husband has tried wax and they do look better for a short time. Is this the correct course of action or is there a better cleaner that we could try? I would like to get on top of this problem, before it builds up too much. We are not able to keep this car in a garage and it is exposed to the elements daily.