I recently boiled a deer skull (w/o the lower jaw) in a large pot in water for approx5 hrs and then went over it w/a small scrub brush. Then I boiled it for another hour. Several days later, I soaked it in straight peroxide for 24 hrs. I then soaked it in water for 24 hrs and it came out AWESOME...easier than I thought...good luck.

PS: Only soak it up to the antlers. I soaked/peroxide mine in a narrow type tupper wear, like the type you would use for cereal.