Friday, May 15, 2015

BONELUST Q&A: "I've been macerating bones & they are now a strange color! Are they ruined?"

Maceration is the process of purification to remove the remaining flesh from bone. It is the easiest & least expensive way to do this while still leaving bones in good condition. Note that this process is typically best for animals larger than a rat. Smaller bones can turn to mush during maceration as they themselves start to break down.

To macerate you take your animal remains that have very minimal flesh on them (never a whole animal!), add them to a plastic container & fill with plain tap water then replace the tight fitted lid. The lid is important because you don't want insect larvae in your maceration water only the bacteria that will grow and eat away the flesh. You also don't want to leave it out in the rain without a lid or you'll get algae growing. Insect larvae & algae with both start to break down and possibly even stain the bone.

The more flesh on the remains the longer this process will take. Somewhere around 2 weeks the bones should be coated with a film that's pink, red, rust, brown or black. That's normal & means the bacteria is working to remove the flesh. The bacteria may however be dead now though so time to change the water if still fleshy and start the process again, or time to start peroxide bath if done. Pour out only half on the nasty water and add fresh water to fill the rest of the container if the maceration is not done yet.

These deer bones were covered with a bright red film because they were left for too long in the maceration process, on accident. They were completely flesh free though. Thankfully I just hosed the film right off then started the peroxide step to get rid of the awful smell.

The odd colored film you see on your bones is a residue of the bacteria or the bacteria itself coating the bone. It does this when the water runs out of oxygen for the bacteria to survive. Referred to as the bacteria going anaerobic. This anaerobic bacteria in maceration replaces the microbes that were doing the maceration work of defleshing the bones. And therefore the maceration process has come to a halt.

It can be caused by too many microbes using up all of the oxygen in the water or it can be from an oily film on top of the water that keeps oxygen from entering the water. Some ways to prevent this are - larger quantities of water, changing the water or a bubbler. It commonly happens to marine mammal remains during maceration because of the high oil content in their bones rising to the top of the water.

This is a potbelly pig skull that started off lightly mummified that soaked undisturbed for 2 weeks. The maceration water was still fairly clear and yet the skull was turning black. I've found that when there is little flesh to work with or very old flesh this can happen. Sometimes the black film easily hoses off or goes away once the bone dries. In this case though it took a peroxide bath to remove the black coloration. 

Raccoon bone that was pulled out of maceration. It was dropped into peroxide and pulled out an hour later to show how fast the peroxide can get rid of the staining. It can in most cases happen instantly.

"Before" of diamondback rattlesnake bones straight out of maceration.

"After" of same diamondback rattlesnake bones after a peroxide bath.

The maceration water needs to be kept at a certain temp to work. It will not work in the Winter in most locations because it is too cold for the bacteria to survive. It will also die off if it gets too hot in warmer months. For exact temperatures & more extensive info about this see this blogspot blog.

Good luck!


james said...

hello! I just came across your blog as i am almost close to giving up lmao

I found a dead opossum body outside my apartment awhile ago (i'll give it 3 weeks or so), I didn't think till about 3days in to try & keep the skull+bones, by the 3 day mark the whole body was completely dry!

the skull looks like it might have some dry skin stuck to it, or maybe that black stuff you've shown in the picture, but I've been looking all over for an anthill to put it on w/ no luck. Someone tried referring to those bone cleaning beetles, but after reading your post I don't think that's the best idea (especially since this is my first try at something like this)

there is still a lot of fur stuck to it, so I've been avoiding soaking it in water w/ laundry detergent since you have to filter it for the teeth, & with all that extra stuff still stuck to it I feel like it'd be hell

I'm sorry is this is something you've answered before, i would just really like your expert opinion on this!
thank you so much for your time!

Jana Miller said...

Hi James! What you want to do is macerate it. For my many blogs that explain in detail how to do that go here -

reel entless said...

ok so i am kinda new to this whole process and have been reading alot and by far your blog is the most informidable site i have found. i am into collection and rearticulating fish skulls. i have done a few on my own with out reading much on the internet and have taken a few learning curves, i was wondering what is the best method of putting the bones back together for the rearticulation? thanks

Jana Miller said...

reel entless I highly suggest checking out my friend Lee Posts' website and buy his related book/s on the topic of articulation -

Anonymous said...

Hi Jana! Thanks so much for running this blog. This past year I've started preserving pig skulls, and your blog has helped me so much.

I was following your advice and macerating my current pig skull. It was pretty clean to start, but I had to manually clean out the brain cavity and sinuses. It had been in the water bath for about a week, and I noticed last night when I changed out the water that part of the skull has turned neon yellow. I figured I could probably use hydrogen peroxide to eventually get rid of the color, but I'm curious what this color might mean and if it's a problem. I haven't seen any red or black like you mentioned in this post.

Thanks so much!

Jana Miller said...

Hey Theresa! Sorry I did not reply sooner. Running a business full time does not leave me much time for my blog. I took a look at your related blog posts and here’s my reply:

That neon yellow is really strange.

One thing I wanted to note is that when macerating you do not change out the water so often, if at all. Ever. I’m thinking that is what caused the yellow color. You want to leave what you are macerating undisturbed in the water at least a week or two for the maceration bacteria colony to grow and deflesh for you. You do not need to do ANY manual cleaning. Maceration takes all of the work out of defleshing for you. Smelling bad, you WANT that. That’s how you know the process is working.

As for your whitening with peroxide - adding a cup to a tub of water with your skull is not going to do anything. You need it to be 100% peroxide if not at least a 50/50 bath with water. For you skull I would go with 100% peroxide. No water.

Take a look again at my maceration posts and peroxide whitening posts, all of this info is there. :)

good luck… jana