I've got a pair of Clement Paris Roubaix Seta tubulars. I don't really know how old they are, but I'd say at least 25 years and probably more. The sidewalls look pretty bad, but that may be purely cosmetic. The pictures show some signs of cracking that I honestly hadn't noticed before. The tread looks good. They hold air pretty well.

Would you trust these tires for riding? Can anything be done to improve the appearance of the sidewall?