How do I clean these??

 

I'd start by getting a Maguires buffing rod/ball that you can install on the end of a power drill. Then get some Maguires metal polish and try buffing them out. There are a lot of metal polishes out there, and some are more effective than others. I've used Maguires for similar situations, though not as extensive as yours, with good results.

 

My old Sportie had the same... I used Flitz then coated with Shark Hide. Never had to do it a second time..