Parts Stop stocks California Custom's Purple Metal Polish and its Aluminium Deoxidiser — the pair that truckies use to bring dull, oxidised alloy back to a mirror. On the shelf, ready to go.

These two are a system, and that's the bit worth knowing: the Aluminium Deoxidiser goes on first and chemically strips the oxidation and milky haze that ordinary polish just buffs over, then the Purple Metal Polish goes over the top and comes up to a chrome-like shine with far less rubbing. On badly weathered Alcoa wheels or tanks, the deoxidiser step is the difference between 'better' and 'crystal clear.' It's silicone-free and body-shop safe, so it won't cause fisheye grief near paintwork. California Custom's made these in the USA since 1989.