I've dealt with this before. I used to own a detail shop so i can speak from experience. Meguiars makes a clay bar kit that should do the trick.
You can usually find this kit at a parts store or possibly wal mart.
The use of it is simple.
1. use a soapy solution with a spray bottle and spray over area, only work a 8"x8" are at a time so it wont dry.
2. while area is soapy just simply rub clay over it a few times, the clay should turn colors as it becomes filled with the contaminents.
3. have a clean terry towel handy to wipe off panel and if it feels smooth as a babys bottom then you've got it.
4. the when you're done clean the area (or car) thoroughly and wax to protect and seal the paint. HOPE THIS HELPS EVERYBODY OUT.
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1994 MUSTANG GT 5.0,5 SPEED COUPE,BLACK EXTERIOR, GRAY LEATHER, FULLY LOADED,STOCK 3.08'S, TIMING ADVANCED 12 degrees, BASSANI BX CATBACK, UPR OFFROAD X PIPE, FRPP 9 MM WIRES, AUTOLITE 25'S, MSD CAP/ROTOR, MAC COLD AIR INTAKE, MAC UNDERDRIVE PULLEYS.
OICI8U2
Brake Dust on paint won't come off? 2003 Mustang GT 
