Well, you could bury the bones and let nature do it’s thing. This works quite well actually, but it takes time. And you run the risk of detritovores and scavengers making off with the remains.
A commonly held notion is that you can boil bones clean. Let me warn you, boiling rotting carcasses is a great way to make rotting carcass soup and a terrible way to clean a skeleton. You know how chicken soup on the stove fills a house with it’s deliscious smell? Imagine that’s a dead raccoon in there. That’ll cure the common cold.
Beetles are the best way to clean a corpse. The beetle in particular is called the Dermestid officially, but goes by many other names like the hide beetle, the carpet beetle, the larder beetle, and the flesh-eating beetle, because of what they eat – everything except glass, steel, and bone. Throw a buffalo sized head in to a container with a thousand or more dermestids, and they’ll leave nothing but the bones in a matter of weeks. Not overnight, but still the fastest game around. Dermestids are handy because they can crawl into eye sockets and nasal passages and get all the meat, and brains, from those hard to reach nooks and crannies.
Dermestids eat cartilage too, which is why you never see a real museum skeleton with the nose bones, ear bones, or it’s chest plate in tact. All of those parts are cartilege. Usually the sternum and center ribs are replaced with synthetics for display purpose. It’s also why you’ve never seen a shark skeleton, despite seeing shark jaws at every corner cabana.
If you want to start cleaning bones you’re going to need thousands of these little buggers. Many taxidermy shops sell guides to raising and using them, and many sell the bugs themselves. Just don’t let them get away. Eating everything is what dermestids do best. Just like the flesh eating beetles in The Mummy movie.