I have a nice set of orig goodyear polyglas gts.
Anyone had any success freshening up the white
letters? Ive used tire marking crayons, they
are marginal at best. Any ideas??
Thanks

Have you tried Wesley's Whitewall Cleaner,Comet or got to a local tire shop and buy some liquid rubber buffer.It is used to clean an area for patching and works great to take of black scuff,top layer of dis-colored white on the letters.Good luck

I use this stuff

Use 800 to 1000 grit wet or dry (black face) sandpaper. Cut into 1 inch squares and then fold the small piece over (in half) twice. This will give you about a ¼ square with enough material to hold between your index finger and thumb. Make sure the tire letters are wet. Continue to dip the small piece of sandpaper in water as you work. Sand the letters until all dry rot or discoloration disappears. BE CAREFUL NOT TO HIT THE SURROUNDING/RECESSED RUBBER AREAS! Don’t worry about going to far. The letters are solid white all the way through to the sidewall. Be patient. It is a slow process but it will make the letters look pure white and new again. Don't worry about scratches in the rubber. The old rubber sands away to a perfect smooth finish. They will also stay new looking with proper maintenance.

(Tire covers anyone!!!)

Tire paint is available on the bag.

Tire paint will never make the letters look new or original again. The small cracks (from dry rot) need to be removed or dirt and discoloration will always plague them. Painting over the small dry rot cracks and rubber oxidation would be similar to painting over pitted or deeply scratched metal. It will always be detectible. I have used the sanding process on every NOS tire I have and they look absolutely new when they are complete. I have an NOS tire that I have not detailed yet. I will post a picture of two side by side letters to show the results. One letter will be sanded and the other will be in 40 year old, untouched condition.

try sos pads

Don't know if you have them over there, but 'Brillo' pads work great ( soap filled steel wool )...

Not to hijack this thread but can you do the same thing with the big rubber bumpers on a 73-74 E-body. Mine look OK but thought if I could lightly sand them they might look new again.

I prefer the sanding method because chemical processes do not allow for error. The purpose is to make the white/letters appear to be new AND untouched. If the black sidewall area surrounding the letters becomes damaged, altered or manipulated looking, it ruins the desired appearance.
Below are before and after photos. If the letters have deep cracks or dry rot, you can use 400 grit wet or dry sandpaper to remove the old surface. The finish of the rubber will still look new and smooth, even while using the 400 grit paper. A raised white letter or whitewall tire has a solid white layer of rubber beneath the thin black veneering of rubber that covers the sidewall. The letters are solid white blocks that allows for the old oxidized/cracked surface to be safely removed. After using the sandpaper, the white surface residue can be cleaned off with lacquer thinner. I stretch a piece of cloth over my finger, dip it in the lacquer thinner and wipe across the face of the lettering. It leaves them as white as they were when new. Keep in mind that there is no paint or fake coating that is left on the surface to rub or flake off. The rubber that remains is completely original and should last for years with proper care!