this works on the black textured part of bumpers, especialy vauxhall corsa wheel arch spats that eventualy go grey, being carefull with a heat gun (paint stripper gun) heat up the plastic gently useing brushing strokes, try on your cars plastics first to get use to the amount of heat that comes out of your gun, but mind your paintwork,and the colour might come back out through the plastic, be careful the plastic doesnt melt or crack. i know cars bumpers are made out of a completely different plastic but it may work, but it works a treat, and makes the plastic look like you have just siliconed it, and stays like that,just a thought, might be worth trying on tatty z rims first...sam