Removing black marks on paint after DE

[larrybard]

Don't know if I'm more likely to get a response posting here, rather than on DE, but I'll try: what do drivers recommend for removing those black marks (presumably from tire "marbles" hitting the car at high speeds)? I am pretty laid back (to put it mildly) about car cleaning, but all those black marks I've been accumulating are beginning to bother me. I can only hope that they aren't corrosive, like bird "residue."

And while I'm at it, another driver suggested applying something like Klasse wax to wheels to help protect against brake dust, but of course that presupposes that the wheels are clean to start with. I fear I am starting to witness the corrosive effects of brake dust on my wheels; I actually tried to wash the dust off yesterday (a rare activity for me), and am afraid that some that didn't easily wipe off may be attacking the metal. Before I try something that might be too aggressive, any suggestions?

Thanks,
Larry