When I buy supplies for my taxidermy, the instruction sheet that comes with the Bleach says this (This is also what I learned in taxidermy school):
"Clean skull of as much meat and tissue that you can remove with a knife. Prepare a pot of water with 4 oz. of Sal Soda to each 5 gallons of water. Bring to a rolling boil and immerse skull. Cook at a rolling boil for 15-20 minutes. Remove and scrape remaining tissue from bone. Return to boiling water and repeat until bone is clean. Note: The object is to remove the maximum amount of meat and fat in the shortest amount of boiling time. This will prevent damage to the bone. Try to clean the skull within 30-60 minutes. Once clean, place skull in a pail of clean, hot water while you prepare the bleaching mixture. Mix Basic White with 40-volume hydrogen peroxide to form a white froth comparable to shaving cream. Remove skull from clean water and pat dry. For whitest results apply to a damp skull. Paint Basic White/Peroxide mixture onto skull until completely covered. Allow to air dry, usually overnight. Wash skull free from dried bleach mixture with clear running water and allow to dry. At this point, skull should be very white. If any areas remain unbleached, repeat the bleaching process."
In my own experiences, find a pot big enough so that the whole skull is able to be submerged, however, try to keep the antler burs out of the water. I will also note that some skulls I have bleached will leach a slight oily/greasy residue over time that makes the skull turn slightly yellowish in some areas. I haven't tried it yet, but, I have heard of doing two different things to degrease them. Either also boil the skull with a scoop of Oxi-clean, or put some dawn dish soap in the bucket of hot water after the boil process and let the skull soak for a while.