Date: Mon, 24 Feb 1997 12:43:10 -0400
Subject: METHODS FOR CLEANING SKULLS
There's been considerable interest and discussion on how to prepare
skulls for display, so I asked our Anatomy Preparator to give me her
methods, and I'm posting them here for the group's use. This is
courtesy of Ms. Pam Arnold, A Laboratory Specialist Senior at the
Virginia-Maryland Regional College of Veterinary Medicine.
One note of caution: ALL of these methods will create a stench like you
wouldn't believe, especially #2.
Methods For Preparing Bones To Be Used For Display Or Teaching Purposes
There are three methods that can be utilized for preparing bones that
will result in a clean, dry, white product that can be handled and
displayed. Skulls are used as examples below:
1. BOILING METHOD:
This method is good for small specimens or when time is short. After
removing the skin and as much meat as possible, just put the head in a
pan of water and boil gently for several hours. Boiling too fast can
loosen teeth and cause them to crack. Remove the head and pick off any
loose flesh. Return it to the water and boil again for several more
hours. After this second boiling, all the flesh should be easy to
remove with a knife and toothbrush.
The mandible (lower jaw) will have separated from the skull during
boiling. Make sure to save all the teeth that may have come loose.
These can be glued back in with Elmer's glue or Super Glue gel later.
Scrub the skull with liquid detergent and a toothbrush, making sure all
tissue is removed. The last step is to place the skull in a 3% hydrogen
peroxide solution until it is bleached white. this should take 3 or 4
days. Peroxide is available in drug or grocery stores.
2. MACERATION METHOD:
The second method utilizes bacteria that are already present to digest
the flesh from the skull.
You'll need a large waterproof trash can with a tight-fitting lid, and
a warm place to store it. The warmer it is kept the faster the process
works. It will also smell pretty bad, so you'll want to keep it away
After removing the skin and as much meat as possible, and removing the
mandible, put each skull in a separate plastic bag, punch a few holes in
the bags, and place them in the trash can, then fill it with water. It
is important that each skull has its own plastic bag so teeth don't get
lost and parts don't get mixed up.
Under warm conditions (80-100 degrees Fahrenheit) the skulls should be
ready in about 4 weeks. under cooler conditions it can take from
several months to nearly a year. When they're done, the remaining flesh
and tissue can easily be removed with a water hose and by scraping with
a knife and toothbrush. Again, take care not to lose teeth; any that
fall out can be glued in later.
The last step is to soak each skull in peroxide until it is bleached
white. Remove the specimen, air dry it, and glue in any loose teeth.
3. BEETLE METHOD:
Use dermestid beetles to clean up your "de-meated" skull. This is
great for younger specimens, which often fall apart in boiling.
Dermestid beetles are the insects in Nature that clean up animal
carcasses. They prefer dried-out material and will not eat skin. To
prepare a skull for "beetling" you need to skin it completely, de-flesh
it as thoroughly as possible, and dry it out in an air current for a few
Then place it in a SEALED container with the beetles. You can get
beetles from a "beetle colony" (most veterinary or medical schools will
maintain a colony for exactly this purpose) or you can collect a few by
leaving your skull out "in the wild" for the local beetles to feed on.
If you do the latter, be sure to put your skull in a wire cage to
prevent other scavengers (dogs, foxes, etc.) from carrying it off.
After beetles "do their thing" (which may take several weeks, depending
on the size of the specimen and how completely it's been de-fleshed) put
the specimen in the freezer to kill the beetles; leave it frozen for at
least 3 days. Thaw out and re-freeze after three days to trick those
that survived the "cold weather" snap and kill off any survivors.
Dermestid beetles are bad news to have in your home. they will chew
through almost anything, including plastic, carpets, and books. Be
certain you've killed them off before you bring the specimen inside.
Finish the skull as mentioned above: scrub, soap, rinse, and peroxide