Cold water maceration, you can't beat it.

Cold-water maceration is the best way, in my opinion, to unaggressively clean bones. After a year in a dustbin underwater in the garden the dolphin skull and porpoise skeleton are a lot more manageable than they were when I first retrieved them from beaches in North Norfolk in 2012 and a cove in Devon in 2013.  I carefully lifted the bones out and where once connecting tissues held them together they are now loose and independent of each other. This presents other problems for the amateur naturalist as they then become easily disorganised. I moved them in small groups carefully to my workshop table and laid them out to dry. Both of the skulls still contained 'material' that had to be removed with a shaped scoop and all of the bones will need carefully cleaning and de-greasing at a later date. It is immediately clear how much bigger the dolphin skull is than the harbour porpoise and also how much sharper the teeth are. The soft material that still remains in the dustbin has been re-immersed and I'll have to carefully pour it through a sieve later to retrieve small bones and teeth, not or the faint hearted. Excited to see how much of the porpoise skeleton there is as I thought it was more scattered by birds, foxes and dogs when I first found it buried in the sand. There are clearly a lot of ribs missing and flipper bones and the matter is made more complicated as I remember that I dropped bits of a seal into the dustbin at some point and so it'll take some detective work to sort out the jigsaw. Everyone needs a winter project.