The wheels on my 1996 XJS are generally in good shape, but there are a lot of fine scratches on them, which really detract. I believe that these are clear-coated aluminum alloy (if not, please let me know). Any ideas on the best way to restore these? I tried to machine polish them with a DA polisher, with limited success. Will I have to strip the clear coat or is there a better way to return them to original.