Hi to all I can recommend purple, as an ex tanker driver all the drivers used purple on our alloy wheels and fuel tanks and they came up like mirrors and made the truck look smik. If you polished them on a regular basis it was an easy job to do, even had one bloke that would lie on his back and polish underneath his tanks and when asked why he would say that if he ever ran over anybody they would see themselves as he went over them. kakadu