El Stupido here ruined a full set of Cokers with a brass wire shop brush. I thought I was being smart not to use a steel wire brush. Either will leave deep scratches on your tires that attract dirt like Lawson attracts girls wearing shorts.
Not kidding google Mr Clean Magic Eraser or better yet go to your grocery & buy a box. Packed 4 pads per box. Made by the makers of Mr. Clean & has his bald head on the box. I got a box in a goody bag & tried them & they do work.
BTW the box says made in germany & distributed by procter & gamble got questions call 1-800-248-1612 box also says www.mrclean.com for naysayers.
Greased lightning works for me,,spray it on and let it set for a few minutes and run around the whitewall with a stiff nylon tire brush,,spray once more and hose off,,it's worked for me for the past 10 years or so. HRP