Barkeeper's friend also works great on plastic car headlights as well.
I've also used Cameo Stainless and aluminum cleanser for both metal and plastic polishing as well.
Cameo is a bit softer on the finish as far as leaving any fine scratches behind.
Vinegar also works well for removing rust.
For most chrome though I go right for the wire wheel cleaner acid, its fast and leaves nothing behind to clean up. Just spray on, and rinse. Just don't get it on skin, paint or aluminum.