All depends on the condition. If it's heavily scratched, scuffed, and stained, then it'll probably need to be sanded down first. I use progressive grades of wet-dry sand paper...starting with 400-500 grit and moving up to 1500 or so. Once the uglies are removed, then I use a plastic polish...the type sold at auto parts stores for refinishing scratched and clouded plastic headlight covers. If it's in decent shape to start with, just the plastic polish should suffice.