Welll, these weren't a complete waste of a dollar when I was twelve. True, you couldn't use these to tease your friends about what interesting underwear they had on or to read the answers to the test in the back of the textbook. But you could make the girls squeal and cover themselves with their hands and then run back to squeal again when you put the glasses back on. At eleven, that's good use of homeroom time.
These things, also known as X-Ray Specs, were sold in comic books and magazines for decades. Maybe they still are hawking the darn things. The trick is that there is a little feather in each lens, which breaks up light enough to confuse the eye. Yes, if you look at your hand, you do seem to see the bones. But if you look at anything else, softball bat or soda can, whatever, you see the same thing - a dark interior surrounded by a lighter area. If you are given to conspiracy theories, you might go around concluding that everything has bones in it. But usually you'd fool around with the glasses a bit, then leave them next to the tank of moribund sea monkeys.