I have polished wheels that looked great on the outside but had a heavy brown buildup on the inside. I decided to give it a thorough cleaning. The most obvious easy way, using EO A2Z, did little. So I brought out some heavier stuff. I used a drywall sanding block made of composite so I don't get rust marks that steel wool would give. I used it to get the bulk of the crud off. I then used NevrDull, Brasso and Wenol red and blue to see what kind of cleaning power they had. The best results I got were when I dipped a wad of NevrDull in Brasso. It enhanced the softening of the brake dust and increased the "cut" of the NevrDull. I also trieda steam cleaner with a brass brush attachment. It worked up to a certain extent but I eventually preferred using the sanding block. I also used a Dremel with a stainless brush to get at the really stubborn stuff. It made short work of it but it was so small that I wouldn't get a uniform finish if I used it on the whole backside and would have been very tedious. After I was satisfied, I gave the tires and wheels a cleaning with EO A2Z. Once dried, I used 2 coating of AIO and 2 of SG. Done. Install wheels.