[hm. Oscar frowned over his dinner, nervous about what to ask but knowing he needed to keep the conversation going. It was only polite...]

Um. Sure, animal skulls are fine. I've heard of people deep in the woods who like to collect them-- and that they actually bury the parts that they want cleaned for months and months before digging it up. All that's left by that point is dirt and bone, so they polish it from there for their shelves.