When other cleaners won't work. Buy this and follow instructions exactly as written. If you did not get them clean and they are slightly brown you probably used BRILLO or S O S which are steel wool and steel wool will rust. Particles of steel wool are left behind in the pores of the white rubber and in a short time they rust and show up as a light brown coloring in your Whitewall. An off the shelf product called Iron Out can clean the rust in your Whitewall. 

Recurring Brown? . . .a week after you clean the Whitewall is a manufacturer problem from running the molds too hot, the preservatives in the rubber compound burn and turn brown. Follow the enclosed directions and all the brown will come out. Call the hotline number on the instructions.