As much as I like Doug's PSP the first thing I usually do is remove the aluminum foil from the package. My thinking is that it takes a lot of space and isn't all that useful to boil water in. And I'm unlikely to be without a steel water bottle. But I have to admit, lately I'm reconsidering the importance and utility of tin foil as a survival item. The main reason? Fire.

So many times the ground is wet or uneven. I've realized just how huge it is to have even a 2" square of foil to collect fatwood shavings or shelter a cotton ball from the snow or wet. It's really nice if you're trying to keep your potassium permanganate in a pile long enough to get it mixed with glycerine.

A bit of foil is also pretty useful as a windscreen, not just for stoves but for keeping that initial tinder pile going.

Probably no revelation for most people, but a sublte realization on my part that foil is handier than I though.