Pepto Bismol, that faintly bubblegum-flavored sludge from your medicine cabinet, was actually once considered something of a wonder drug. Bismuth subsalicylate (BSS), the active ingredient in Pepto, is derived from Bismuth salts. Even as a salt, people have used bismuth since the 18th century for its anti-inflammatory, bactericidal, and antacid properties. And when mixed with zinc salts, BSS forms a potent remedy for diarrhea—perfect for treating cholera-infected infants in the days before penicillin.

In this semi-instructional short by Melanie Hoff, we see how just a dash of muriatic acid and foil can strip bismuth metal oxide from the rest of the medication, leaving only an iridescent pile of slag. No, obviously, you shouldn't try this method at home. [Wikipedia]