Having just recently purchased a set of wide white walls from Diamond Back
Classics, I thought I'd chime in with their suggestion on keeping things clean
(from their website):
We recommend frequent cleanings.
Avoid any sealers or products such as Armorall. These products are great
for the black portion but not for the whitewall.
Castrol Super Clean is recommended and is available at most auto parts
stores and at Wal-Mart & K-Mart.
Use an abrasive cleaning pad. 220 -440 grit wet/dry sandpaper is best.
I haven't had the tires long enough to try this yet but will once they start
getting dingy.
Jeff
'56 Sedan
Trenton, NJ