Clay bar will remove residue but not damage to the clearcoat. Let me guess the spot looks like fine nicks in the surface in a circle right?. Get the spot wet if it goes away then it is in the clearcoat and has not gotten down to the basecolor. Use some ultra fine paper like 2000 grit and some polish by machine or hand and you should be able to remove the spot. Watch that you don't go to far I don't think Ford puts a whole lot of clear on their vehicles as compared to GM witch I'm used to dealing with.
Matt
01 S-10 crewcab
83 Mustang GT some mods.
