It seems that many of the really old tubes faired very well over time, but I did take a few tires off of old bikes that had the old orange/red color tubes melted into the something that resembled chewing gum. I spent the better part of a day trying to melt, scrape, and peel what remained of a pair of tubes from a pair of JC Higgins drop center rims from the late 30's. Since the tires were Allstate, there's a good chance the tubes were original. They were huge size wise, at least what was left of them. It was hard to tell if they just softened up and stretched out though. The tubes were sort of a red/orange color but the valve stem was black rubber. The stuff was melted all down around the spoke nipples too. Once I finally got the spokes loose, I ended up using a wire wheel to get the rest of the tube off the rim. I'm not sure what caused them to melt like that but the tires were just as gummy and sticky. Another bike sitting next to it was the same way. The grips, tires, and tubes were sticky/gummy like the rubber had melted and stayed melted. The black valve stem portion of the melted tubes was fine though, other than being glued into the rim.