Years ago I went on a binge and ordered three different 1 lb bags of clay masks: one White Kaolin clay, one French Green clay, and one I can't remember what it was. I've only used the French Green clay mask a handful of times. It does tighten up the skin, though I have to use it only on weekends when I don't shave.
Actually, this weekend seems to be a good time to try it, since I'll be out camping (and therefore not shaving), but I'm afraid it will project the wrong impression among my fellow campers.