Bear Skull

Beatles or macerate and then into heated dawn/water until done.

 

If you are looking to do a book skull, beetle it and let it just dry for the required period of time. Have it officially measured and recorded then finish the degreasing with heated Dawn/water. Letting it sit for a while will possibly prolong the degreasing but maybe not if it is sitting in a cooler area that prevents the grease from softening and creeping deeper into the bone. You could also soak in acetone which will not affect the bone in any way. Using just acetone will take forever for a bear if it does any sort of good job at all. Acetone is great for bird and fish bones or thin, delicate bones. Heavy thick bones like a bear, not so much.