Bf Goodrich brown walls
I have had many brands of tires with white walls or raised white letters.
I always had problems with the black of the tire smearing on the white if I whipe the tire all at once. if I use a clean towel and wipe only the white areas it stays white.
I haven't had BFG tires in decades. Do t recall the problem back then.
I have Cooper Cobra RWL out, and the foam I noted earlier seems to work well.
Spray all 4, go back to the first, stiff brush, rince well, move on