I'd try clay bar (mothers and meguiars both make it). It seems to clean up most stuff from track days or autoxing (ie cone rash, rubber streaks and tar). Good luck!
Yup, clay bar ftw! I use Clay Magic, which can be found at almost any local auto parts store. Also, check out www.autopia.org for more tips.
before a claybar I'd try washing it very well and then trying a little bit of cleaner wax. Some good car polish works too.
I went to autozone, got some mequires piant cleaner ($5.50) and some of the turtle wax compound for swirl marks and scratchs with the green label, not the red ! The green labeled stuff has milder abrasives in it ($2.18). The paint cleaner didn't do a thing . The turtle wax worked good, took awhile but got it all off. I tried it first in a spot no one could see to see if it would hurt the clear coat but no issues with that. Waxed it and it looks great, nice and smooth. Some small scratches left behind, but very hard to see.