Folklore is right.
I didn't make, but bought, one off the eBay site, and it has kept exactly the same as it was the day I bought it. I guess I just haven't had time to toss it out yet. Now I know what's in it, I'll be less concerned about some sort of damage by tossing the thing. Unlike the Galileo thermometer which is pretty and actually changes, and with some science behind it, this thing doesn't even attract attention.