This is a skull from an old collection that I bought at an auction. Was really greasy and nasty to handle. Appears to have been boiled and never degreased. Has been sitting in straight ammonia now for 8 months. The ammonia in the bucket was nasty slime and discolored when I pulled the skull finally. Several rinses and soaks in hot water to where it is now. Still grease to be seen but it is already 100% better. Going to let it dry some and see. Might be going into an acetone bath after this. This is a Russian brown bear from Okhotsk, Russia. After a looooong soak in straight ammonia. Before when it first came home. As a reference, the odd skull next to it is a capybara. Biggest one I have ever seen at a smidge under 12 inches long. The other is a huge reticulated python.