Westleys Bleach White, as its name implys contains bleach. I recently contacted the tire manufactures about the brown bleed through problem on the white sidewalls. They all recommended not to use bleach or any product containing bleach on rubber. I now use Simple Green and a lot of elbow greese.
I've tried everything and nothing works like Harley Davidson white wall cleaner. It will make them snow white with very little effort. Dad's white walls had turn brown and it made them snow white. Try it and you will be shocked at the results!