The cleaning process that I use has been tweaked for years but I feel confident in my process now. The story about how I came to this process is placed in my bio in the About Me section of this site. This section will be giving you the exact process that I will be using to clean the skulls that you would like to display in your home.
Step 1 - De-fleshing
This step starts after the head is taken of the body of the animal. The head is still fully intact. You start by skinning the head and taking off all of the fur you can to reveal the flesh. You can then cut off the large areas of flesh on either side of the cranium and jaw, while taking out the tongue and the throat flesh as well. The eyes then need to come out as the beetles do not really enjoy them as there is too much liquid in them. You can pull them out with plyers and then cut the back nerve that attaches it to the skull, it should come out with a little frustration. By sticking an object in the back and "messing" up the brain you can then pull it out of the main cranial hole in the back of the skull. You can then pour it out with running water in and out of the cranium space. The skull is then ready for the beetles.
Step 2 - Dermestid Beetle Cleaning
My beetle colony is now running year round as I have built a weather proof container that keeps the temperature stagnant and the humidity high enough that they are comfortable. Since the skull has all of the major fleshy parts taken off, it will be cleaned much quicker by the beetles. The beetles will only eat dried meat products so this is why all of the flesh is taken off so that it is quicker to dry the skull and prepare it for the beetles. It is important to always freeze the skull before placing it with the beetles, if there is any chance of maggots or other parasites on it. I usually freeze the skull for two days to kill off all possibilities of maggots because they will destroy an otherwise healthy colony of beetles. I place the skull into the beetles with a tray under it just in case any teeth fall out or bones were broken in the skull from a road kill situation. I check on the skull daily and when I am able, I pull the jaw away from the main part of the skull. Taking the pieces apart ensures them being cleaned to the utmost quality. The beetles eat in stages of muscle/flesh, tendons, cartilage and checking on them will point these stages out. In the later stages, the skull has to be dipped into water and cleaned a little bit with a brush. Then the beetles are rejuvenated to eat the rest when it is a little moistened. Once the skull is completely cleaned it can be taken out and rinsed with water and scrubbed with an old toothbrush. Careful to not lose any teeth or pieces in the process.
Step 3 - Degreasing
For this step I use my own degreasing agent to dissipate the yellow colour of the lipids that have soaked into the skull. Many times the skulls of the meat-eating animals come out of the bugs being a lot more yellow than the herbivores so this step is almost always necessary. You can soak the entire skull in the degreasing agent for as long as you would like and the grease will collect at the bottom of the container. I like to then air dry the skull for a few days until it appears dry the entire way through the skull.
Step 4 - Whitening
This step is the most finicky. It has to be done carefully and using peroxide. If this is done with bleach the skull will most likely flake apart over the years and be extremely fragile. Done with peroxide you will most likely not have this problem. At the end of this step the skull should be cleaned of all smells, discolorations, and oils if they did not disappear before. The skulls is now clean and ready for display.
Step 5 - Sealant (Educational/School Use Only)
For the skulls I take to the classrooms I end up sealing them with an egg shell wood sealer because some principals do not like carbon material that could possibly carry things that could potentially make people sick. It is also makes some of the more fragile parts more durable and acts as a light glue for some of the smaller teeth.