I agree if all the meat/tissue is off the skull it more than likely is brain matter that is making the stink! For removal of the brain matter I use a arrow shaft via the brain stem, just after the intial boil. If possible rinse it out with a garden hose or if your like me and often do this in the dead of winter where a outside water source is not a possibility, then use the pull nosel from your sink or in the tub! (It is advised to wait till the lady of the house is good and gone before attemting do such a procedure[8D]!).
The other possibility for smell is the top roof of the mouth, I use a small caping knife and remove this when fleshing and fresh. If you don't plan to do the caping/fleshing fresh (soon after the harvest), then wrap it tight in garbage bags and throw it in the freezer till you can get to it. I have done this several times and works great, much better than having to deal with staining or dried meat!

As to bleaching I pretty much do as other have said. Flesh it as best I can, wrap antlers tightly in alum. foil, thenboil in dish soap or even pickling salt (outside) & pull it out every 30-45 minute of gentle boiling pot to remove loose matter. Once I have obtained aclean skull it gets boiled for up to hour in the same solution, then let it air dry. Finally to the bleaching I have used several ways that work well, best is peroxide soaked gauze and leave it for 24 hours, then rinse off and air dry. Also tried peroxide & dry bleech to form a paste this year and the results were very good. Again I left it on the skull for 24hrs, then rinsed offvia garden hoseand air dried before completing the project. The absolute worst thing is using household bleach it will cause a yellowing tinge, especially over time.