Cleaned it the best I could, getting as much meat and brain and hide removed as I could.
Boiled outside (don't do it indoors, unless your wife is reallllllly understanding) for at least an hour. It is not a pleasant smell.
As it boiled, I removed more meat that loosened. Used a thick leather welders glove to hold the skull, since it was hot.
You can do the lower jaw if you want. It won't stay attached, but you can wire it in after the cleaning process. Or a dab of epoxy.
A buddy of mine sticks his in the dirt and covers with chicken wire, so critters and dogs don't haul it away. The ants, worms and bugs clean his all winter. Then rinse it clean in the spring and bleach.