dollar store peroxide is only 3% but will do the trick, the more expensive food grade 35% can be found at health food stores, but it's costly.
Bear skulls first need about 4-6 days in a grease pulling agent like a dawn dish soap mixture. Some use white gas. After that is done (never had to do that for a deer) a peroxide bath for up to a week for bears, a little less for deer. keep the H202 away from sunlight and give it access to O2. It can be a challenge keeping the antlers away from the peroxide. Hope that helps. BCB
The only things I do differently are I cut the back of the skull off to scoop out the brains and I use electrical tape to tape the antlers and keep the peroxide mixture off of them, seems to wrap tighter. The powder and gel are found at Sally Beauty in the blue mall off Dorset street. I bought a quart and the small pail of powder, I do a few a year and that quantity will last me a long time.