I work at a place that gets this red stuff, I'll have to find the name at work, but my red truck had a nasty underside from oil and road grim about 1/2in thick in places, sprayed it on and let it sit, when I came back it was falling off the truck.... The stuff worked, it took the weatherproof grease off of some of the wirerope we make, that was scary. I now use it on the trucks every chance I get. It takes tar off without me wiping it and never once hurt the clear. I got to figure out what it is, I swear I have never seen anything like it. Took the rubber off the vettes wheel wells like it wasn't there. I'll find out what it is and maybe you can get it somewhere near you. I know some dealerships have it but use it for other things. It has to be safe for vehicles though to be in there.