Use tar remover to remove road tar and insects. Never do this with a knife or similar tool.
To prevent corrosion on bright-metal surfaces, apply wax or chrome preservative and rub it to a high luster.
During cold weather or in coastal areas, cover bright-metal parts with a coating of wax or preservative heavier than usual. It would also help to coat them with noncorrosive petroleum jelly or some other protective compound.
Do not use steel wool, abrasive cleaners, or strong detergents containing highly alkaline or caustic agents on chrome-plated or anodized aluminum parts. This may result in damage to the protective coating and cause discoloration or paint deterioration.