OK, those of us non-newbies to the BMW brand who have been driving one for a while know the scourge of brake-dust, etc. that conspire against keeping our wheels clean, almost as soon as you turn off the hose and put away the cleaning products. Or, maybe it's my driving/braking !! Anyway, I found something that works GRRREAT and keeps the wheels cleaner longer. Perhaps you all have heard of it but it not, consider this a suggestion...it's called "Keep Clean Wheel" by Eagle One. 18 Fl. OZ,. available pretty cheaply at Pep Boys. I gotta tell-ya - this stuff WORKS! Right after washing the car, you spray the wheels completely - full coverage is important here - and let them dry @10-15 mins. before driving. It's really that simple. It keeps brake dust, road dirt, other wheel dirtying scourges away from your wheels for up to 2 weeks.