Butane lighters will eventually leak and become worthless. Here's a (theoretical) way to store them so they last longer. Please note that I haven't tried this (because I don't rely on disposable lighters) but it should work...
Put a small canning jar, seal, and band in the refrigerator until they get cold, then slowly take them out, add your lighters, and seal them tight. That's it, yer done.
The idea here is that when the jar gets to room temperature, the air inside will expand. This will put the contents under a little pressure. As long as the pressure outside of the lighter is higher than the pressure inside of the lighter, it can't leak. In fact, the higher pressure outside should actually force the valve to seat more firmly.
Even if the lighters do leak a little, they should stop as soon as the pressures equalize. The lighters inside should remain usable as long as your container can hold the pressure, which should be a very long time. If you ever need to open the container and remove a lighter, just repeat the process with the remaining ones.
A Bic lighter can be invaluable. If not to you, then to someone else as a gift, for barter, etc. Thanks for the tip. I also don't know if it would work or not but you got me thinking. What about vacuum sealing them in a bag?