The best product for removing soot and the easiest on your finish is a product made by Stoner Porducts called...."Tarminator".It is also very good for removing tar,line paint and sticky residue from decals that you remove.It will also remove overspray from your finish if you get a little paint happy on your uindercarriage(found that out when a buddy of mine was detailing his truck underneath and mine was on the lift next to it and it got covered).

 

good option Hammer, Tarminator is amazing stuff, but one can lasted me the bottom half of my truck for tar once and that was all!

 

tarminator is amazing

 

My diesel and my straight piped WRX both sooted up the rear end nicely. I've always just used Meguires wax and polished it off. Both vehicle are white and it took it right off.

 

there is stuff you get at an auto paint store that painters use its a wax grease remover called dx330 made by ppg. its like 20 bucks a gallon and does a great job. doesnt hurt your paint. just throw a little fresh wax over it after your done and your good to go

 

I've always had good luck using a mixture of Simple Green and Dawn dishwashing soap. That and a little elbow grease should take it right off.