The door moldings of imported cars (Benz, BMW, Audi, etc.) are not plated like domestic cars, but aluminum material with alumite treatment is used.
Therefore, in a hot and humid environment like Japan, "white rust" like a dull white color often occurs on the surface.
White rust is difficult to remove with normal abrasives, and there is a risk of peeling off.
At our shop, we use a special polishing agent to remove as much white rust as possible, and a special coating agent to prevent white rust from reappearing.

​In many cases, replacing the molding with a new one and polishing when the white rust has progressed is very expensive, so early polishing and coating are recommended.