If you've ever done one of these you know what a pain in the @ss they can be. This way takes time but almost no effort.

I have done many and they turn out excellent. Skin the head and remove the bottom jaw, thensubmerge it in a 5 gal. bucket of water.
wait 2 weeks and change only half of the water, when you do this squirt it down with the hose, wait another 2 weeks and repeat that........normally within a month to 6 weeks the skull will be clean as a whistle. Boil it for a few minutes to kill the germs.
When you remove the head from the boil and rinse it, paint/coat it with a mix of boric acid and peroxide. Let sit 24 hrs and rinse.
Thats it.


http://i92.photobucket.com/albums/l16/texas8point/samrusty8.jpg