I bought brand new Moto Metal Chrome wheels about 18 months ago. I have tried to take great care of them and keep them clean and polish them. yet I'm getting all these discolorations and raised bumps in the chrome finish. It's past the warranty so there's nothing I can do in that department. Also, the chrome is chipping off of the plastic center caps. What the hell?! These weren't cheap wheels. What should I do?