I forget where I read it first, but it's been suggested that you can super-glue flints for a Zippo lighter to the side (in the groove ) of an old key or a blank, and use that along with another key or a P-38 for a striker. If you don't use a Zippo and/or don't want to buy the flints, you can pull the flint from disposable lighters once the gas is gone. Most of the time, the left-over flint is still pretty long (longer than the replacements for the Zippo in fact).

Troy