I would use PH neutral citrus degreaser since there are chrome wheel cleaners that contain acid.

 

Ended up using steel wool and a coat of liquid glass. They came out well enough and don't appear to be clear coated. I don't have a before pic, but they were pretty gross. Stored in someone's garage prior for a couple years and it looked as though they'd taken them off mid winter and never cleaned them before storage. Por 15'd the entire inside of the rim too. Just over $100 for a set of 4, so I'm not complaining.