Are they magnesium or Aluminum? Either way wash with a degreaser like Purple Power or one of Zep’s Industrial Degreasers , glass bead, wash with an acid based mag cleaner, wash with degreaser again. Dry the wheel in an oven to get all the moisture out. Prime with aircraft zinc chromate if mag, if aluminum wash with Alodine then zinc phosphate prime and paint. For paint I used Rustoleum high performance enamel. The rustoleum fillis the pin holes well. Did is to my American mags years ago and no leaks ,no peeling either. Used Gibbs penetrant on the exterior of the wheel . Just did some pitted Hilibrands and they are holding air.