[legion]

I'll have to check the bottle when I get home, but I think I use a 70/30 mix of distilled water and glycerin. (Maybe it was polypropene glycol? I'm not sure.)

Anyway, any decent tobacco shop should carry the stuff. My humidor has a nice brass gauge in the underside of the lid and a green-spongy thing next to it that I put the mixture in to keep it humid. I've never done anything to the interior wood (occasionally wipe down the outside with Pledge) and I've never had any mold problems. I just fill the green-spongey thing about once a month.