Went for a blast about a month ago and there was the usual rain and dirt on the ground. Left car in garage. Anyway took the car for a wash today and the wheels have what looks to be corrosion on them. They are only on the rear wheels. Front are fine.

I tried using an alloys wheel brush and soap and it wont come off. I then used a slightly abrasive dish cloth on a small part of the wheel and presto it comes off. But only after a good while going over the patch.

Anyone know a way to remove this crap from the wheels. Never seen this happen before. The alloys are Ruff alloys and were cheap which is probably why they are $hit!

Cheers