Funked, Clay bar will take the overspray black paint off your finish. Just make sure you do the following: (after you get the car back from the auto body shop, I HIGHLY suggest doing this anyway!)
~Get a good quality clay bar (Pep boys will carry a good brand)
Buy some Detailing spray (Meguiars Quik Detail spray should be sufficient.)
~Wash the car with Dawn dish detergent (about 1/4 cup to 3 gallons should be sufficient) to strip the finish of all wax. (And while your at it, buy some good car wash, don't ever use Dawn except to strip the wax off)
~Rinse, but keep the rinse water on.
~Kneed the clay to about the size of you hand,flattened out like a small pancake.
~Use the detail spray to lubricate the surface (along with with rinse water that was left behind from washing it) Work the clay bar over the entire finish, beginning at the top and work your way down to the bumpers and rockers last (These will be the dirtiest with tar balls, contaminents embedded in the finish)
~Rinse the car again when complete, or better yet, re-wash it.
~Dry it and wax it again. It'll look just like new.
You can get about 7-10 good cleanings with Claybar, so store it after your finished. Contrary to the old wives tales of yesteryear, claybar will NOT scratch the finish. Trust me, I have a Jet Black finish and JB tells you everything! Use it only when you plan to wax, but make sure you strip the old wax or reminence of the old wax off with Dawn detergent.