Is there a chance this information could be made into a sticky...
+1 for a General Flashlight Maintenence sticky
I've got a bit of background on this, as one day I decided to sift through the CPF archives regarding lube to get some answers. Hours later, a few points were clear:
-You can use pretty much anything to lube a flashlight, since there's nothing to corrode and modern o-rings are impervious to petroleum (and will eventually wear anyway). Vaseline, teflon tape, bike grease, etc, whatever's clever.
-Most of the good lubes "feel" the same. There isn't any particular one that makes the threads magically better over the others, so getting fancy/expensive lube is purely optional.
-Don't mix more than one kind of lube on the same place, otherwise the less viscous lube will "float" on the other one, making things way too slick and/or messy.
-Conductivity is a non-issue; If "non-conductive" lube made a flashlight inoperable, it wouldn't have worked when you first took it out of the box.
-Look at the places that sell flashlight parts/accessories for flashlight lube, it doesn't have to be a goose chase.
-There is no one single "correct" way to clean a flashlight. Rubbing alcohol and a makeup sponge, WD40 and a rag, placing it in a dishwasher, etc. Just avoid abrasives.
So that's what I've culled from a few years worth of posts on the subject. And I personally use rubbing alcohol/rag to clean, and Krytox 50/50 to lube.