Here is an older link, but I don't think there is any recent "new" fix...
hard water, acid rain, etc., is the culprit. I use Zaino on my '01, and
while the spots do come back to some degree, it has never been a real
problem, cosmetically. Maybe I just got lucky on my trim...
GL, mD
http://www.xoutpost.com/bmw-related-...ter-spots.html