My strange and wonderful 6-year old has an obsession with bones. She even asked me if she could have my bones when I die. I said yes, but since we aren’t at that point yet, right now we are gathering all sorts of animal bones and cleaning them. 🙂
I read a lot about how to clean bones on the web. The general consensus is that:
- Never use bleach to clean bones. It will destroy their structural integrity.
- Only boil bones to clean them if you have no other means. And, from my experience, boiled bones don’t look as nice as ones cleaned with hydrogen peroxide. They get all shiny when boiled.
- Hydrogen peroxide is the best amateur method for cleaning bones.
First I’ll talk about how to clean bones with just hydrogen peroxide. Then, I’ll tell you a good hack using baking soda to clean very large bones.
*By the way, if you are looking for cool gifts for anatomy-loving kids in your life (or adults!), these are awesome! Yes, these are affiliate links – but it’s how I keep my site going. 🙂
Which Hydrogen Peroxide to Use to Clean Bones
The hydrogen peroxide that you buy in drug stores comes in really small bottles, and is usually at a concentration of 2%.
Yes, you could use this hydrogen on bones, but you’d need a LOT of it and have to soak the bones for a long time. Instead, ask your pharmacy for bulk hydrogen peroxide at 20% (or higher) concentration.
I couldn’t find any pharmacy which carries 20% hydrogen, so I had to find a hookup who works in a pharmacy to special order it for me. It pays to have connections!
*If you can’t find 20% hydrogen, you can use hair developer. It is basically hydrogen (with some perfumes and alcohol mixed in). You can buy 40% hydrogen hair developer on Amazon here.
Cleaning Bones with Just Hydrogen Peroxide
At first, we were just cleaning small bones like sheep jawbones that we found while hiking in the countryside. This was easy. Here’s how to do it:
- A bucket or Tupperware slightly bigger than the bones you want to clean
- A lid for the bucket (or improvise one out of a plastic bag)
- Dish soap
- Old toothbrush
- 20% (or higher) hydrogen
- Water for diluting
- Rubber gloves – absolutely necessary! Hydrogen will turn your fingers white.
- An outdoor space – hydrogen stinks and you really shouldn’t breathe hydrogen vapors in.
1. Remove soft tissue
If your bones have soft tissue or rotting flesh on them, the easiest way to remove is it is with maceration. Basically, you put the bones in water and let them sit so natural bacteria can remove the tissue– potentially for months. I live in the city, I don’t think my neighbors would like to see (and smell) rotting bone tissue in our communal yard, so I personally have never done this.
Alternatively, you can bury the bones. Bacteria will eat away at the bones (and maybe some worms will eat it too). But this also takes a long time.
The most practical method for removing soft tissue from bones (especially for city dwellers like myself) is to use biological cleaning powders/enzyme stain removing powder such as Biotex (which you can buy here) These cleaners contain enzymes which will break down the soft tissue. Just soak the bones in a solution of the powder + water until the tissue becomes soft enough to scrape off.
*I haven’t tried this personally, but Jake of Jake’s Bones uses a baby bottle sterilizer for cleaning tissue from bones. He warns that it will smell disgusting!
2. Pre-clean the bones
This applies to bones you have found which do not have any soft tissue on them, but are caked with dirt and maybe have moss growing on them.
Use soapy water and the toothbrush to SCRUB the bones clean. The cleaner they are when you start, the better the hydrogen peroxide will work.
3. Soak the Bones in Dish Soap
Bones actually have a lot of fatty oils in them. If you try to clean them with hydrogen peroxide before removing this oil, you’ll see it float to the top of the brine. Gross! So soak the bones in soapy water for at least 12 hours. If they are really gross, then you’ll need to dump the water and re-soak.
4. Now Soak in Hydrogen Peroxide
Put the bones in your bucket. Pour in your hydrogen peroxide. Then top it with water. The bones will start foaming, which means the hydrogen is working. Hydrogen also heats up when it is working.
I couldn’t find any information about the exact ratio of hydrogen to water for cleaning bones. Basically, the higher the concentration of hydrogen, the faster and whiter your bones will be. Unfortunately, that can mean spending a lot on hydrogen. That is why it is so important to find a container which fits your bones exactly. The less excess space around your bones, the less hydrogen you will have to use.
For my small bones, I used a ½ liter of 20% hydrogen plus about 1 1/2 liters of water. They came out clean in 1 day.
5. Cover and Leave for 24+ Hours
It is important that you cover the bones once they are in the hydrogen solution. The lid will keep the fumes within the bucket and help it work better.
I didn’t have a lid for my bucket the first time I cleaned some bones. So, I just put a plastic bag over the top to seal the bucket.
*Note about Cleaning Very Dirty Bones
Isabel found this extremely dirty bone that was sitting in a river for god knows how long. It had all sorts of river scum on it. I cleaned it with soapy water (skipped the soaking step though because we were in a hurry to finish before moving to a new home).
Then, because I couldn’t find a bucket to fit it, I used a method that I’d tried with other bones: Put the bone and peroxide in a plastic bag together. Tie and let soak.
Well, the peroxide went crazy on this bone! It started steaming and got HOT. I thought it was going to melt the plastic bag!!! You can see in the picture all of the steam coming off the bone.
Eventually I used a plastic drawer tilted on its side to soak the bone in. The hydrogen didn’t go as crazy on the second round, but still bubbled a lot. The bone came out nice and clean. At least cleaner than how we found it. 🙂
Using Baking Soda + Peroxide for Cleaning Large Bones
Isabel’s friend found a cow’s skull for her (what other 6 year old is lucky enough to have a friend who saves bones for her?). The skull was free of soft tissue, but was still really dirty and stunk badly. I didn’t realize it smelled so badly until halfway home on the bus. Sorry to all the people who had to put up with the rotting smell on the 30 minute bus ride! 😮
Cleaning such a large bone presented some problems:
- I literally could not find a plastic container large enough for soaking the skull. Not even laundry baskets were wide enough to fit the horns.
- I would have had to use TONS of peroxide to immerse the bone. I’m not a rich person and wasn’t thrilled about spending $50 on peroxide for a skull.
My first (unsuccessful) solution: Soak the skull in a doubled trash bag
I put the skull into a big trash bag, poured in some hydrogen and water, and then tied off the bag. I kind of propped everything up in a plastic drawer.
The peroxide did whiten the skull a bit, but of course the trash bag sprung a leak. The peroxide pooled at the bottom, so only part of the skull got whitened. You can see a line on the skull from the part which was sitting in the most hydrogen solution. It looks terrible!
A better solution: Mix the hydrogen with baking soda
Baking soda is a natural cleaning agent, right? Could I mix it with hydrogen peroxide to form a paste, and then spread the paste on the bone?
I did a small test batch and the baking soda and hydrogen mixed well.
The great thing about the paste method is that you don’t have to use lots of hydrogen and it can be spread in all those weird nooks and crannies skulls have. The only annoying thing is that you will have to do at least two rounds – one for the top of the skull and another for the bottom.
Here you can see the before/after pictures.
The skull is hanging in my daughter’s room, right above her Hello Kitty covered bed with a mountain of stuffed animals. The perfect décor for a little girl. 🙂
And here it is in infographic form. Feel free to Pin It! 🙂