I tried Merlin's blood on both mine and my wife's SUVs, I have to say this is the best stuff I have used to clean these 20-inch wheels. I used a 3100 PSI pressure washer and spray the hell out of the wheel with just water and it was still nasty with brake dust and dirt. After it dried so I could see what it looked like, I sprayed with Merlin's blood it started bleeding pretty fast, but I waited about 4-5 mins and hit it with the pressure washer. The end results were amazing, looked like a brand news set of wheels.

Now I must say, this stuff has a bad odor. Get past that and you will have some clean wheels!