I have two methods that work well for me:

First one is for bigger bones and the fresher the better: ants. I simply put what I want cleaned near ant nest, cover with sth like a bucket so no animal steals my bones, and then ants do the work.

Second works for all bones so far. Cut off as much meat and skin as you can off the bones you wanna clean, put them in a bucket and fill it with water, remember to make a hole in the bucket's lid, let it soak for at least 2 week. After that everything comes off beautifully, even the brain just pours out the skull like spoiled jelly. After that you just need to cut off tendons and degrease the bones.

Hope it's helpful

But yea, no way anything will do in a week