White letter problem with bf goodrich tires

Take some 240 grit wet/dry sandpaper and a flat sanding block, and wet-sand the discolored rubber off the letters or the whitewalls (only!). All white letters and whitewalls have this discoloration problem, and have had it forever. This is the only thing I've found that really works, and if you are careful the sidewalls and your wheels will not be damaged. Can't say the same for brillo pads, harsh chemicals, etc...