Be careful of many of the wheel cleaners available as quite a few have acid in them that etches the wheel surface and makes brake dust stick even more than before they were cleaned/etched. Acid can cause a lot of damage if not completely flushed from all metallic surfaces. P21S has been very good for years. I did not find the Griots, BMW OE or Simple Green to be as good as the P21S. Recently I tried a new wheel cleaner from Germany sold by Sonax. This stuff is amazing and it will take all of the brake dust off the wheels including brake dust that is etched into the wheel surface. It is pH balanced and contains no acid. It actually reacts with the iron in the brake dusts and converts it. I've seen pics on several BMW forums of this stuff in action and my results were very similar. For baked on brake dust you do need to use a brush but it will remove all of the brake dust, which P21S never did for me. I've used Wheelwax, Ultima Tire & Wheel dressing and I'm currently testing RejeX. It looks like all of these wheel polymer sealants are removed faster with wheel cleaners than with car soap. Depending on the brake pads you use, driving habits, etc. you can probably use car wash soap for a few months then remove the wheels and use wheel cleaner to get all the brake dust off on the back side of the wheel and re-apply your favorite wheel sealant.