BROWN TIRES AREN'T JUST DIRTY. THEY'RE GUNKED UP WITH OLD DRESSING.
That grey-brown film is three or four layers of dressing that never fully came off, oxidizing one on top of the next. Soap won't touch it. Neither will a stiff brush on its own. You have to strip it, and that's what Wise Guy is built for.
It's a non-acid, high-foaming cl