My car has the optional factory leather / aluminium door sill. I can't explain the part but I'm N O T looking this part: Image Unavailable, Please Login But this inner (optional) part: Image Unavailable, Please Login There's some soot there after a major overhaul of some parts. This copper paste + oil + grease + whatever mixture stains have been on that part for a while, +2 months. I tried to remove it by applying a brake cleaner and got almost nothing removed. So is there anything else I can do? I cannot even figure out the proper word / name for that part in order to search from ebay or such.