There is a product on the market called "back to black" in a spray can. Halfords usually stock it. Doesn't have to be used on black bumpers only but works equally well on all shades of grey. Highly recommended.alans220 said:Hi, Just a wash with Autoglym shampoo and cold water. It was really nice to wash, but the black plasticky trim was difficult to clean, might need something special to clean that with.