i clean up any died matter ,which hasn't been much so far and can be done with toothbrush and pocket knife.
then i wrap the horns in saran wrap as the soulotion in the following step will cause whiting of the horns real fast.
glue back in any bones or teeth that have fallen out and i have had the upper bones come out forward of the nose,usually by ruff handling.
then mix a solution of salon care 30 or 50 volume creme developer and quick white super strenth powder purchased at salley's beauty supply,for a few bucks. this will foam some.i then just paint on and wait 30 minutes and rinse off with water hose.
let the skull sit for 30 minutes to an hour,i usually fling arrows during the waiting parts ,as it will whiten some more as it sits.