So I've got a set of '18s I'm looking to sell. After cleaning them up, the front side of each wheel is immaculate, no spots whatsoever, just a couple chips. The back side is a different story. There's a few little spots where its corroding and bubbling the chrome. Any way to treat these little spots? I can carefully remove the chrome chips forming, bead blast (after covering the rest of the wheel of course) the spots and then what? Any way to protect the metal?