I was thinking something along the lines of Flare, the self-lighting ciggarette trick, but just using the same principle... ingredients, if you like, on a card. No idea if it will work though.
Those flash cards look awesome though, thanks for that
However, mandrake, you idea sounds rather dangerous! Lighter fluid + finger flasher = me on fire. Getting the fluid onto a card would be a challenge in itself without getting it on clothes/skin.
Are you just looking for me to set myself on fire? lol
