I also saw something about shocking the orings back to elasticity. (hot hot water, then ice water.) I don't know if it works, but it's something I have filed away in my brain on the off chance I need it for leaky tanks, or ... maybe a u-can.
O-rings are cheap, I plan to replace them in my U-Can if/when they start to leak. The steel parts should last for years ...
I would stick with silicone o-rings, they use them in food preparation machinery, rated as safe if ingested ...