Skull cleaning is a great way to preserve the bones of dead animals that you may find while on a walk in the forest, but how do you clean animal skulls? This is probably one of the most commonly asked questions that we recieve at http://www.boneshoppe.com/.
First and foremost, we do not condone the killing of animals only for their bones. This short tutorial is to help you preserve FOUND bones. We believe that if you kill an animal - you eat it. Also, this article is for information purposes only. We assume no liability if you attempt skull cleaning! Please be aware that there may be species of animals that are local to you that are legally protected species and you cannot use their bones, even when found dead and this includes road kill too. Now, on to the instructions.
There are many methods used to remove the flesh from an animals skull. Some people use dermisted (flesh eating) beetles as they can provide one of the cleanest end products without you having to get your hands too dirty. Other people may use boiling water, however this is very tricky as some skulls (mainly smaller animals) can turn to mush if boiled too long.
So, the focus of this article is going to be (in our opinion) one of the simplest methods and one of the most basic taxidermy skills for skull cleaning and is ideal for the novice bone cleaner. We are going to discuss cold water maceration.
What exactly is cold water maceration?
In the easiest description cold water maceration is placing a skull in a container of cool water, covering it with a tight lid and letting nature take its course. The natural bacteria in the water will begin to break down the flesh on the skull within a matter of days. In essence what you are doing is using water to rot the remaining flesh from the bone. After about 4-5 days, you can change the water in the container if you'd like. For a small animal skull, it should be completely clean within about 5-10 days. To help this process move along faster, remove as much flesh as possible from the skull, by hand, prior to putting it in the container of water.
A fair warning though - when you open the lid on the container, it will smell VERY bad and it should go without saying. Think about it - you've been rotting flesh in an enclosed area for many days. The smell of wet death is not very pleasant, but this will get the job done to clean the animal skull without the use of chemicals, beetles or guess work. Once you are ready to remove the skull from the now rotten flesh soup, remember to wear THICK nitrile or rubber gloves. If you use your bare hands, the smell of rot will seep into your pores and stay there for quite a long time.
After all of the flesh has been removed, you will want to thoroughly wash the skull with water to help remove the smell and any lingering flesh remanants.
** HELPFUL TIP ** >>> As the skull macerates in the water over the days you leave it in the container, teeth will most likely fall out and depending on the age of the animal when it died, small bone pieces may fall apart as the cartilage deteriorates. The easiest way we have found to contain all of these pieces is to put the deceased animal specimen into women's stockings (dollar store ones work great) and tie off the open end. By doing this you won't have to fish around in the bottom of the container, through all of the rotten flesh and muck, to find a couple of teeth or small bones. This also works great for entire small animal skeletons such as mice, rats, birds, etc...
OK. So now you have a defleshed skull, but it's not entirely clean, yet. For most small animal skulls, the process of maceration will also remove most of the natural oils found in the bone, however if it does not, or if you are macerating a skull slightly larger, you will want to degrease the bone to remove these oils.
There are many opinions available on what to use to degrease skulls. We will only share what we use and find to work best for our needs. This is not to say our method is the best one out there, but we find it works perfectly well for the end results that we are seeking.
Once the skull is thoroughly washed, we let it air dry for a few days and then, in a very well ventilated area, we will submerge it in a small container of regular acetone (available from any hardware store) for anywhere from one day to several days, depending on the size of the skull. Once we are satisfied that the skull has been completely degreased, we will remove it from the acetone and once again thoroughly wash it with plain water. We have never seen a skull or bone be harmed by the acetone.
Once the skull is washed, we set it aside again, to air dry for a few more days.
As soon as the animal skull is dry we now have a choice to make. We can leave it the natural bone color that it is and just seal it with a matte varnish sealer - OR - we can "bleach" it and turn it a nice whiter tone.
Most times we opt for the natural bone color, however perhaps you would like the whiter tone. For the novice skull cleaner, the easiest way to achieve a lighter bone color is to submerge the skull in hydrogen peroxide for as many days as it requires to achieve the color you are looking for. 3%, available over the counter will work OK for smaller specimens, however for larger skulls you will want to consult a taxidermy supply company for 12% - 14% peroxide and follow the manufacturer's directions.
After you are satisfied with the color, once again, remove the skull and thoroughly wash it. Then set it aside to air dry for a few more days. Once the skull is completely dry you will want to seal it with a varnish sealer - matte or gloss, the choice is up to you.
Should you need to re-attach any loose teeth or small bone fragments, we have found the best glue to use is Zap-A-Gap, but be warned - this is not just a regular super glue. This is like super glue on steroids. It bonds almost instantly on bones and on skin it will bond instantly and slightly burn.
So, there you have it. A beginner's guide to the basics of bone cleaning. It's not all that difficult to achieve nice reults with this method and is perfect for anyone looking to start animal skull cleaning as a hobby.
Jesse A. House