that might also be the tire shine stuff. both of my cars get tire shine slung on the fenders if I drive within 1 or 2 hours of cleaning 'em

 

on the t/a is it definately rubber. that **** does not come off for anything

6 years of street racing has a tendency to do that

 

I had some on my Mustangs fender also. A bud showed me this stuff called Goo Gone. It works really well to get that crap off. Also, at Wally World, the sell this bottle of tar remover that's about $4.00

a little elbow grease and that liquified rubber will come right off