After reading an exhaustive treatise on this and performing on wife's EOS, I thought " better living through chemistry" and thought how of how I get brake dust off? Meguires of course, so I masked off tip and surround and sprayed McGuires wheel cleaner( this stuff is supposedly approved by wheel mfgrs) on and into tip. Let it set for a minute and then hit with a rubber brush designed for wheels....viola!,,,stains gone...apply wax and wait for next time.