For anyone watching that, this guy has some really horrible advice. Including deliberately damaging a skull because your method of cleaning is poor. To get those mineral stains out of your skull, you need to soak it in a solution of powdered Iron Out. 1/4 cup to 4 to 5 gallons of hot water. Let it sit for a few hours and when it looks good, remove it and rinse well. Don't ever heat or boil peroxide. Huge waste of product. Soak your skull in straight peroxide overnight and it will be as white as it can get as long as the grease is out of it. You might be able to force it a little more by pasting it as above with either Basic White (also from where you get the 40 VOL peroxide) or at the least, talcum powder. Wrap it with plastic wrap and get it under a heat lamp or into a very hot area. UV has nothing to do with pushing the peroxide to whiten more, it's heat. After baking it for 24 hours, rinse well in hot water and it won't be any whiter. If you do use the Iron Out, do not use peroxide after doing so. Your stains will return with a vengeance. I made a post about this with photos on a different taxidermy board.

If at all possible, macerate/rot your skulls clean. Boiling causes a lot of other issues and you will take more time trying to correct those than if you rotted it clean to begin with. Maceration of a deer skull takes 2 weeks at the most if done correctly. In addition, a lot of the oils and grease in the skull are broken down by doing it this way and finishing it is a lot easier. Boiling will cook the grease into a skull and you will pretty much never get it all out.