You might try clay-barring it. I had a couple of spots like that and no cleaner I tried got it off. On a whim, while I was claying my rockers, I gave the wheel a quick hit. Came right off!! It's worth a shot, as the clay wouldn't force you to re-clear.

BrApple-its all in the way it is presented...but everythign on my resume is all me TexasRealtor-I hope you spelling improves on your resume. MxRacer-ladies and gentlemen, welcome to ironyville. population, texasrelator.