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My brilliant new clever invention for cleaning bones


For ages I have been thinking of a better way of cleaning bones with biological washing powder. I have been using biological washing powder to clean for almost two years now after it was recommended when I visited Perth Museum. I wrote more about it in my complete guide to cleaning bones, but the way it works is it contains enzymes which eat away and dissolve fat. 

Up until now the way now I have been putting the bones to be cleaned in a plastic container, adding the biological powder, then adding hot (not boiling) water then leaving it for a while, then adding a new lot of hot water and powder. The problem is that when the water cools it doesn't clean as well so it takes lots of changes of water.

So I have been thinking for ages for a way to do it easier, where it's nice and clean, and it heats itself. Then two weeks ago I was at a nearly-new sale with my family and Dad saw this and wondered if it might work....

It is a baby bottle steriliser, but from now on in it was called the Super Superb Skull and Skeleton Sterilising System (or the S6 for short) ! It isn't designed to clean bones or to heat big loads of water but dad had a close look and thought it might work, then he gave me the £5 to go buy it. This is how it is designed:

You are supposed to plug it into the mains and a heating element (like in a kettle) at the bottom heats a tiny amount of water which turns to steam and sterilises everything. But what dad spotted was that the whole top part could contain water so it could heat the whole lot.

I had a whole load of things I could have cleaned with it but I decided to carefully test it on some bird heads that Mr Evans had kindly given me earlier that day. Here are two fulmars, which had been collected in the 1990s and never cleaned:

The heads were dried and mummified which is normally very difficult to clean. You could still see the hyoid bone which the bone that controls the tongue in birds. When the skull is skeletonised this bone is often lost because it isn't properly connected to the skull.

The steriliser had trays that fitted inside. I put the skulls that were intact inside containers so no small bones would be lost. Sometimes you could take the beak sheats (which are the cover the end of the beak, made out of the same stuff as hair, nails and sheep horns) off. You can see here a fulmar in the yellow box, a razorbill in the round cup and a greylag skull. I have already taken the top sheat (scientists call it a rhamphotheca) off the razorbill but I couldn't get the other ones off yet. This is important as you'll see later.

This is what it looked like ready to go in. It looks so neat and tidy that mum didn't go mental about it like she normally does.

The second tray on top makes sure the containers and bones don't float up.

You plug in the steriliser and it keeps heating up the water. Before it starts to boil you need to switch it off because it doesn't do it automatically. It holds the heat really well for hours, and Dad would switch it on on in the middle of the night when my baby brothers woke him up. In the morning I came down and opened it up.

The water was very mucky and looked a bit like sick. The smell was a bit disgusting.

This next picture is of two different skulls after their first night in the machine. They are a puffin (with sheats taken off) and a fulmar (with sheats still on).

It was a big improvement but still not ready.

I used a knife, pliers and tweezers to take off the loose flesh.This was a pretty gross job but it worked.

You had to be really careful. After the first wash all but one of the rest of the sheats came off and I kept them separately.

This is the razorbill and the second fulmar after a second wash. The cocktails sticks are for taking off bits of flesh. The small bones are quadrates which are the hinge of the jaw that only birds have. You can see on the left that the bottom beak sheat on the razorbill never came off although it went soft.

Here are the before and after pictures for the skulls I tested the Super Superb Skull and Skeleton Sterilising System (patent and trademark applied for):

The Fulmar, before and after:

The Fulmar took three overnight cleans. The sheats came off after the first clean, and I had to take loose flesh off after the first clean. The quadrates came loose after the final wash and needed to be carefully glued back on.

The Puffin, before and after:

The beak sheats came off right at the start but were fragile and a tiny bit got broken. The rest of it took two overnight cleans in the S6. The quadrates stayed on throughout.

The razorbill, before and after

This took two cleans and the top beak sheat came off straight away, but the bottom one stayed on throughout. You can see that the washing took off the bottom white stripe on the bottom beak sheat. This makes me think that the white stripe is like a thin bit of paint on the surface, rather than being like a stick of rock where the colour goes all the way through the sheat.

The greylag goose: before and after

I didn't really need to do this one but I did it as an experiment just to see the difference it made. It made an amazing difference, but it loosened the quadrate bones. It only took one overnight clean. The bottom picture doesn't have the quadrates glued back in yet so the skull looks less tall. This is the four parts of the skull before it was put together again.

This is the best thing I have ever bought for £5. I need to add a timer or thermostat to keep it warm all night without it boiling. The other good things are that mum lets me have it in the kitchen (she usually makes me put things outside) and it tidies away nicely.

The only bad thing is that the size of it is small, so anything larger than a fox skull wouldn't fit. It is a shame because I have a red deer stag with antlers that I found a few weeks ago I need to clean with this method.

Dad made me add this bit: this is not what these things are designed to be used for so if you do it and your house burns down don't blame me.

Update: After I wrote this blog, Jana Miller wrote on her blog about how she uses something similar to clean her bones.

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Living Characters said...

Your latest endeavor with your "S6" was a fantastic find!!!! Great job in sleuthing the alternative usage!! To me, The Greylag Goose was the most impressive. I have always just par-boiled my bones (just short of a boil) for several hours to loosen & clean them so I do not see why a bottle sterilizer would not work. ;)

Jake said...

The best thing about the bottle steriliser for me is that it looks nice and clean for mum.

Ray said...

Very Cool! Thanks for sharing Jake! Much appreciated :)

Wendy said...

Hi Jake!
Great idea, thanks for posting that one. I use a jam boiler at the moment, but now I may try your method.

Jack N said...

Hi Jake, your comment displayer at the side seems to be broken.

Anonymous said...

Hi Jake!

Your site is very interesting and useful :)

You say water in the container cools rapidly.
This problem is easily solved.
Buy aquarium heater, it will always keep the water warm.


Jake said...

Thanks everyone !
@Jack: Thanks, have taken it off for now.
@Anonymous: Thanks for the tip but I actually said "it holds the heat really well for hours"

Tina Driskell said...

You could try putting a water heater in a bucket for the larger bones. They sell them to keep stock animal water buckets and troughs from freezing up. You could also try an aquarium heater.

Jake said...

Thanks for the tip !

Jenny Barnish said...

Hi Jake, I used an electric crock pot for my cat as it doesn't boil and you can leave it on safely all night. It took a few goes but works a treat.

Elizabeth Ploog said...

This is a good idea I might use it on the white tailed skull I found :) . Just one question, I'm new to bone collecting and before I start cleaning I would like to know how you dispose of the water? Does the bio. washing powder hurt the environment?

Thalictri said...

I used something similar to this method on a wallaby skull - Instead of a bottle sterilizer though, I used a rice cooker, set to "warm" which holds slightly more water and then keeps it at an even 60ish degrees. It's brilliant, and cheers for sharing!

Jake said...

Thanks ! I now use a slow cooker overnight which seems to work well as well.

Elsa Becker said...

Hi Jake I am a science teacher from South Africa an I would love to speak to you about doing piglets. I am concerning it as a project for my grade 10 learners. I would appreciate it if you could email me on elsabecker@vodamail.co.za. What a greater idea with the bottle warmer. ELSA

Charles said...

whoop whoop. South Africa! :)
Question: did the school allow you to do that? I heard most schools don't allow that kind of stuff anymore. esp. Govt schools. /:

I live in Germany now and its pretty rubbish about sciency stuff. Like, apparently its even illegal for me to pin insects. I just gave my 300something insects to the University of Johannesburg because I had nowhere in SA to store them and I couldn't bring them over. Would have preferred to give them to a school, but didn't have the time or transport.

Goodluck with the bone project!

Adair said...

Thanks for sharing! I have a bird skull that I've been unsure how to clean - this seems perfect!

A note about aquarium heaters, they work great, but make sure you keep the heater clean! I used one to macerate an elk cow head in cold weather, and over about a week a layer of stubborn gunk (bacteria? unsure, it was dark and smelled awful :) ) started building up and eventually shattered the glass heater. I should have been more on top of brushing it off!

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