What kind of wheels are they? Are they Volk or Work wheels? If so, it'll be almost impossible to get those out because there's an anodized clearcoat on the outside lips and looks like the stain either got through it or ate through it. The only way to do it would be to strip the clearcoat but then the lips will oxidize every few days.
EDIT: I have read that a Claybar could work, or a 50/50 water & vinegar solution may work. I'd be really careful with the vinegar though since it's acidic...