In message , Graham.
wrote

Well my wheel-nut covers were fine before they washed my car after
servicing it last time. Perhaps they used an angle grinder and not a
PW? And no Skoda jokes Mr Lang!
http://www.flickr.com/photos/g3zvt/6...ream/lightbox/

I'll bet that they sprayed the wheels with a fairly aggressive acid or
alkali wheel cleaner before pressure washing and that is what has
damaged the finished surface on the nuts.

My local car wash starts with spraying a solution on the wheels using a
hard "garden pump up sprayer" followed by lather socked brush to remove
bugs and bird ****, followed by a quick pressure washer around the
wheels and windscreen, followed by the trip through the rotating
knives[1].

[1]
http://www.youtube.com/watch?v=e2PyeXRwhCE

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk