Things You'll Need
Non-porous mixing bowl
Even after being stripped of soft organic tissues, an animal skull requires proper cleaning before being used for education, art or decorative purposes. Bleach cleaning both whitens the bones and disinfects the skull, yet bleach soaking may prove inconvenient and inadequate. Instead, create a bleach paste that will sit on the skull without soaking.
Measure 3/4 cup baking soda into a non-porous (metal, glass or ceramic) mixing bowl, or a disposable dish.
Add a cap full of bleach to the baking soda at a time. Stir and mix with a metal fork. Continue adding bleach gradually and stirring until you create a mixture with a paste-like consistency.
Adjust the quantity of bleach in order to thin the mixture to the consistency you want for your project; thicker paste will stick to the sides and undersides of an animal skull, but a thinner paste will flow and smear more readily into cracks and crevices.
Apply the paste to the animal skull using a small craft brush. Thoroughly rinse the brush immediately after use to preserve the bristles or use a disposable brush.
Let the paste sit in place for an hour.
Rinse the skull in water to remove the paste. Re-apply paste to portions that didn't get bleached white enough the first time.
Consider mixing two batches of paste; one thick and one thin. Apply the thin paste first, to bleach out crevices in the skull, then apply the thick paste to stick to the sides and bottom.
In addition to bleaching with paste, a raw animal skull should be soaked for at least an hour in a solution of one part bleach and 30 parts water; this will disinfect the skull inside and out.