I seen someone had asked about these earlier today and I can't find the question now, but I mentioned it to my son in law this evening. He said he asked his Pharmistist if they did any good and he was told no. Said they can't keep them on the shelves but if you take one of them and peel them off and lay them on the counter they will turn dark by themselves.
Imohr, I was the one who asked about those. Somebody mentioned heavy metals and I remembered an advertisement for these that said they draw heavy metals and toxins out of your body. Sounds good if they worked. Hard to believe they are flying off the shelves when they really don't work. They're in drug stores, variety stores, catalogs, and everywhere. So they turn brown even on a counter? This is really funny.