did you know..

That UV lights are really just flourescent lights with small amounts of mercury added to them? When energized, mercury emits UV photons.

Also works with a laser, too. Zap mercury gas with a laser, and you get a UV laser that can be seen when you put a piece of paper in front of it (the UV reacts with the blue fibers manufacturers add to paper to make it appear white instead of mashed-up-tree-goo-brown). But.. realistically.. who's got a portable lasers laying around?

Any rate.

If you're trapped in an Alaskan town when vampires attack, just find a mercury based thermometer, modify a flash light, and there ya go. Point the beam at a sheet of white paper and make sure there's a glowing blue dot before you go on offense, though.