I've played around with various brake cleaners and brushes on our older cars but I just don't seem to be able to get them looking fresh. I'm sure it has to do with the coatings (Stock, not painted) but I've always thought there has to be some way to keep that silver/grey coating looking new. Is there some contaminant remover I should be trying? Am I missing something or is nothing short of a disassemble and severe scrubbing going to help?