De-greaser is as simple as soaking the cleaned skull in water, but you can use "super solvent" which is sold by Mckenzie Taxidermy supply. Dawn dish soap in a bucket of water works as well, but isn't quite as strong. I know that bears and bores have a lot more grease impregnated in their skulls, and some guys will use acetone with good success. I've heard some guys will use household ammonia too, but I've never tried it. If you are going to boil the heads to get them cleaned, then you will definitely be adding grease to the bone of the skull, so use a slow simmer if this is how you plan on removing the meat. Don't bother trying to use ants or fly larvae, because that just doesn't work effectively enough. Dermestid beetles work well, but you'll still need to soak the skull to get the rest of the meat off the skull. The easiest way to remove the meat is to just soak the meat in water, and let mother nature and natural bacteria and enzymes do the rest, but it stinks to high heaven. I use a high pressure washer with the water jet fanned out to it's widest point, and just spray off the rest of the meat. for whitening, you can use 35% Hydrogen Peroxide which you can buy pretty easily at a chemical supply company. 55 gallons costs around $400 from Viking Chemical, but you can whiten quite a few skulls with 55 gallons. If you go on-line, you will find food-grade peroxide that costs a considerable amount more. You can also buy %40 gel at any beauty supply company, but I find it less effective than the less viscous stuff at the 35% grade. Don't use bleach!
Any other questions, just give a shout.