I own a car that was poorly tuned when I bought it and has left the car with a buildup of carbon on the paint. Multiple attempts at washing reveal that the carbon is pretty stubborn, so I've purchased a clay bar kit. Before jumping in though, I want to be sure there isn't a better method someone has discovered.

The extreme a/f's this thing was running led to pulling small droplets of oil out the exhaust due to the fuel thinning that was occuring, so the carbon has a stickiness to it. I've since retuned the car and all is well, but the carbon remains from earlier and its time to get it fixed up while it sits in the garage waiting for spring.

 

wash it down with dish soap first. than whatevers left should come off with the clay bar. if it doesn't some all purpose cleaner would work on like meguiars APC.

 

X2, dish soap is a good place to start. Clay bar would be fine, as would a pre-wax cleaner/fine polish.