As far as i'm aware it's not corrosive, just that if you leave it longer there it'd be harder to clean the wheels.
Motor May 2001 Quote: "Believe it or not, there are actually a bunch of weirdos out there who reckon a six cylinder is the dux gutz. Bugger it: I'm one of them" :s5
AUII Late Ed XR6 HP T5 Venom- Full Tickford Body Kit, 17in Wheels, Herrod Bi-plane Spoiler, Momo Steer/Gear, T-Series Interior Options, Premium Stereo and a very light-tuned 4.0L I6
(FPV-Tickford Club of NSW Member and Co-Founding Member of 3FB Inc, Ford Forums Food Bandits)