It's hard to tell from the picture, but it almost looks like scrapes from where one has used a tool to remove the center cap. If not, it's probably some form or lime deposit or calcification. I'd take the caps off, soak the area with distilled white vinegar for 5-10 minutes, then gentle agitation with a toothbrush and/or a microfiber towel.
__________________
2017 X5M - Current
2017 F31 Wagon - Current
2014 M5 ZCP - Retired
2011 135i Coupe - Retired
2007 335i Sedan - Retired
|