Anyone here ever us a handwarmer? I realize that it isn't even glove season yet, at least where I live, but from what I have read of those who live in Alaska, they can't be beat for keeping your hands warm. I doubt I'll eve own one (don't live in Alaska) but I have always wondered about them. The question that is always on my mind when I see mention of them is, how do they work? They use lighter fluid, do they not?