Very common on diamond cut finishes, unfortunately the only way to get rid is to refurbish them. Diamond cut wheels while stunning are very open to whiteworming if the lacquer gets chipped or scraped (curbed) which is what you're seeing.
You can either get them refurbished again in Diamond Cut (but it doesn't solve the problem entirely if the lacquered finish gets breached again) or get them refinished in standard powder coat which will eliminate the whiteworming but loses the mirror like finish.
