So here's what we have after 3 days of soaking in ammonia, you can see the water is discoloured and there is congealed grease floating on the surface. The next step is to rise these off in warm/hot water, scrub again with Dawn, to get the grease pulled to the surface off. Let that sit in warm water for an hour or 2. Rinse well, and set another ammonia bath. I use the cut gallon container so I can just throw this one out.

Don't reuse ammonia, use new stuff. I get mine at the dollar store, it's a dollar, even if you don't go there to pic it up a gallon is usually only 2.99 or something.

Let this set for another 2 or 3 days. I'll actually give them a swirl whenever I can think about it to help get the fatty oils to the surface so more can be cleared off the bone.

You may have to do this a few times, It all depends of how much residue is on your bones.