Whitewall cleaning

[sabre]

Does anyone have a miracle method for whitening whitewalls. 
I'm trying to clean some marks from the new whitewalls on the Excalibur in preparation for CMC day and the more I scrub the worse they look.
I think  need some sort of rubber paint but don't want anything that will crack.
Any suggestions?

[racingem]

I have used a cloth with metho or thinners .Cant remenber which one it was.

[MADVET]

I'll share a secret that I've used since the good old days of white lettering on tyres.
I use wet and dry sandpaper of about 400 to 600 grit with soapy water.
It will bring up your whitewalls or white lettering to look like new.

[gtc]

I use pumice stone, obtainable from pharmacies in the foot care section. Works a treat, especially on raised lettering.

[72vet]

Kerosene was my choice when I had BF’S on the car.

[Jethro]

The old Solvo soap works a treat 

[sabre]

Thanks for the great advice. I've learned a lot about whitewall construction today.
Tried the solvents but the texture was the problem and getting the gunk out of the pores was going to be an ongoing problem.
Apparently whitewalls are cast under the outer layer of black rubber and the surface is skimmed off to reveal the white. On the Maxis tyres I have the skim left a texture like chatter you get with a blunt lathe tool. I tried the wet and dry with soapy water but ridges at either side of the white left marks on the inside and outside of the white area. I ended up grinding the ridge using an air finger sander then blocked the white smooth. This appears to have left the finish smooth and in the future I hope I'll be able to just clean with a solvent.
While I had the wheels off I took the opportunity to clean the spoked rims. What a pain!
Thanks again to all that provided advice.

[StephenSLR]

The trick is to clean them the moment they get dirty, if you leave grease, etc. on for long, the rubber will absorb it over time and become stained.

s