Installed New Carpet from ACC

inner carpet sill plates.
Bumpers are chrome, the inner sill plates are anodized aluminum. The anoziding process puts a micro thin layer on the surface of the aluminum to stop corrosion, unfortunately the discoloration that forms under it is also protected by the anodizing.
The trick to get a good polish on anodized aluminum is to get the anodized layer off. Search you tube, there are videos on home methods. Or if you are near any large to moderate sized city there is probably a metal coating - processing plant in your area that does anodizing. The one near me actually stripped the anodizing off my door sills for $20.00 and handed them back to me. The door sills then polished up fine and I returned the door sills where they re anodized them at no additional cost. They look factory new and will stay that way a long time. If there is a professional car restoration shop in your area, ask them where they send their aluminum parts for anodizing work, they also would know where to get it done.