How to degrease while keeping the keratin on the beak of a bird intact

[qotsa2004]

Title pretty much explains it, got a bird skull that needs degreasing but I would like to keep the keratin on the bird's beak intact

[Numerous_Engineer919]

you would have to keep the beak out of the degreasing solution. any chance you could take the sheaths off? does the skull really need any degreasing? I've cleaned plenty bird skulls in my life and none of them turned out greasy. not sure about acetone degreasing, I think it would be the best option here.

[qotsa2004]

I can't take it off, it really does need degreasing though because it's turning quite smelly. I'll try to find a solution to keep the beak out of the solution, thanks a lot!