Howdy! First time poster. Long time hunter.

I found a freshly dead deer in the woods 8 months ago. Took the head, skinned it and buried it in a tub. 8 months later I dug it up. It’s almost done (some flesh is still stuck in a few holes). Downside is that at some point water filled the tub and stained the skull a chestnut brown. It’s currently soaking in a bucket of hydrogen peroxide. Ive been checking on it but it’s still very brown. What should I do to whiten it? I’m considering simmering it in a pot with peroxide but it would have to be inside as I live in an apartment. So I wouldn’t want to do that unless I was sure it would get the job done. I can’t hang it up outside to sunbleach because my landlord would get pretty peeved. Plus I’d worry squirrels would get to the antlers. Any advice?