I can't even think how old my can of Coleman fuel is. I bought it back when I actually backpacked, so that is on the order of 14+ years. The can was opened when I bought it to fill the aluminum bottle for my old whisperlite stove.

I was recently given an old Coleman lantern my Mom found at an auction in her neck of the woods. The carrying case for the lantern is steel - the thing is built like a battleship.

Filled with the fuel from the (now rusty, but not rusted through) can. Had to dismantle the pump and wipe some gunk off the leather, then was able to fire it up without any trouble.