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Oxidation Method - Skeleton Cleaning

Preparation of Ligamentary Animal Skeletons 

This is the preparation of ligamentary animal skeletons via the "Oxidation Method" using hydrogen peroxide. This is something I stumbled across while working with students who didn't follow the directions. It is essentially using an ammonia solution followed by concentrated hydrogen peroxide soaks to dissolve the soft tissue from around a skeleton leaving a whitened ligamentary skeleton behind. A major advantage is a small skeleton can be prepared without any objectionable odors or toxic chemicals. Someone was quick to point out that it is unlikely that this is really a new technique, as people have been working with skeleton cleaning for a couple hundred years. However, I have never seen anything in print on this technique and one of the main ingredients (concentrated hydrogen peroxide) wasn't produced much before WWII even though it had been first discovered in the 1880s.

Multiple experiments done by one fellow bone enthusiast on mice failed to produce a satisfactory ligamentary skeleton. My attempts on shrews and voles also failed. The joints came apart or the bone dissolved before the flesh was all gone. But, on small birds (saw whet owls) I have had very good results. The last owl I did (a window-killed saw whet owl) was done as follows: I skinned and gutted the owl, cut off the wing and tail feathers, soaked the carcass in 50% household ammonia for two weeks, then rinsed it. The carcass was then soaked in 17% hydrogen peroxide (H2O2) for ten days--it could probably have gone for two weeks. The flesh ballooned up and got soft and white. The flesh could mostly be snipped off with small dissecting scissors. It was then put back in a fresh 17% hydrogen peroxide solution. The bones were then checked daily. The skull was removed first as soon as it looked like the eye rings were separating. The rest of the pieces came out at the end of the ten days. The remaining flesh was gone or clear, except on the feet and around the neck vertebrae. These sections were put back in the solution for another seven days and the rest of the pieces were posed and dried. The result: A fully articulated small bird skeleton done with a minimal amount of hands-on time (about eight hours) and no stinky! The finished skeleton is clean, white, degreased, and articulated. (See photos below.)


​I am still experimenting with this method and probably will be until I get it all figured out. If you try it, I would greatly appreciate hearing from you. Please send a report to me of exactly what you tried and how it came out to There is a brief write-up about this method in the Small Mammals Manual, and a more complete write-up in the Bone Builder's Notebook.

Tessa Hennigan's Oxidation Method
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Oxidation Method Specimen Cleaning for the Impatient Articulator


  • Select & thaw specimen if frozen

  • Skin, gut & remove as much tissue as possible(time depends on specimen/skill/detail)

  • Place specimen in hydrogen peroxide in vented container(to avoid explosions), tissue should immediately start turning puffy & white.

  • After about 20-30 min, remove from peroxide and using small scissors/scalpel/etc, remove as much of the tissue as you are able. (Again, time will depend on many factors)

  • Once you’ve removed as much as you can, place back in peroxide and repeat.

  • When finished for the night/length of time you have to work in specimen, rinse well with water (don’t want to cross H2O2 & ammonia) then place in an air tight container filled with clear cleaning ammonia.

  • When prepared to remove additional tissue, rinse well and place back in fresh H2O2.

  • Repeat cycle of h2o2, tissue removal,rinse, ammonia night soak, rinse, h2o2 until most of tissue has been removed. Keep in mind, when specimen dries, the remaining tissue will shrink up and be less obvious, do NOT over pick around joints, connected areas or you’ll be left with a jigsaw puzzle.

  • Be sure to flush brain matter out, using a larger needle/syringe, puncture a hole on either side of the base of the skull near the atlas bone, inject h2o2 inside flushing till clean.

  • Do not let your H2O2 go to water, change it to fresh daily. Avoid direct sunlight as this degrades h2o2.

  • When ready to pose, use whatever works for you to keep in position- I use skewers and bug pinning pins on styrofoam. To keep rib cages full, I carve a chunk of expanding foam to fit and then wrap in seran wrap.

  • I speed drying with a heated dryer, spending extra time to focus around skull to blow out any moisture or remaining tissue.

Claira Mittman Results Using the Oxidation Method

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Claira oxidation method was to

use 12% hydrogen peroxide.

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Baby Opossum 

Baby Opossum 

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Tyana King's Oxidation Method

Tyana King of Washington State, prepared the skeletons of a Townsend's mole and a baby opossum over a very short period of time using hydrogen peroxide, hot water and the careful use of a pointed scalpel.


She started by skinning, gutting, and removing the bulk of the flesh from the bones. The head was removed. Over a period of a couple of days, she alternated from soaking the bones in hot water, then scraping sections with a scalpel, then soaking them in 3% hydrogen peroxide, for up to a couple of hours at a time. Obviously, she did this very carefully. When it was clean enough for her, the still articulated skeleton sections went into 3% hydrogen peroxide for whitening and a final soak before being posed and dried.

The baby opossum took one day. The mole was worked over 3 days. Tyana's method is not really oxidizing but it is a good example of another method of preparing small skeletons without having a beetle colony, or dealing with stinky water, or having to assemble a few hundred tiny bones. Best of all, it is possible to have a finished skeleton in a matter of days, rather than weeks. It still takes a lot of patience and meticulous scraping.

Townsend's Mole (Scapanus townsendii)

Townsend's Mole (Scapanus townsendii)

Townsend's Mole (Scapanus townsendii)

Townsend's Mole (Scapanus townsendii)

Townsend's Mole (Scapanus townsendii)

Townsend's Mole (Scapanus townsendii)

Baby Opossum (Didelphimorphia)

Baby Opossum (Didelphimorphia)

Baby Opossum (Didelphimorphia)

Baby Opossum (Didelphimorphia)

Meg Lyman's Oxidation Results
Bat (vespertilio)

1. Skinning. I did more flensing after the picture was taken. Left the eyes and brain in.

Bat (vespertilio)

2. Mid ammonia soak. Straight household (clear) ammonia. Total time was about 3 weeks. Took it out once during that time to remove eyes, brain, and do more flesh removal. In this pic the brain is still in.

Bat (vespertilio)

3. Middle of peroxide soak. I used 35% food grade diluted about half, and it had been used before. Did not refresh it. Peroxide time was probably 6 weeks - could have taken it out earlier for sure. Removed once for more flesh removal during that time.

Bat (vespertilio)

4. Posing / drying after final flesh cleaning and a rinse in water. Used a Cheezit box and packing tape.

Bat (vespertilio)

5. Complete

Bat (vespertilio

6. Close up

Stillborn Puppy

A stillborn puppy. One of Meg's newest Oxidation Method skeletons

​Hollis Dahn's Oxidation Method Experiment

This Cuban tree frog (Osteopilus septentrionalis) was done by Hollis Dahn, from Georgia (formally of Florida). The frog was skeletonized by the oxidization method, using only 3% hydrogen peroxide (no ammonia), over a two month period. The hydrogen peroxide was changed daily for the first week and frequently thereafter until done. No stinky - no degreasing - no extra whitening needed. Hollis is now trying the same technique on an iguana.


​Rachael Rooney's Oxidation Method Experiment

Below is a skeleton Rachael Rooney, a proud college student in Homer, Alaska, did as an independent project. It was done on her kitchen countertop at home using hydrogen peroxide and ammonia to oxidize the skeleton. The bird (killed from hitting a window) was a specimen turned into the Pratt Museum, Homer, Alaska. The rib cage was in rough condition, the rest of the skeleton was great. Rachel's scientific write up about her project appears below the photos. This is the first skeleton Rachael had ever processed and articulated. I gave her a hand gluing the rib cage together on one side. Otherwise, she did it all at home. It is now flying somewhere in the collections of the Pratt Museum.


Rachael Rooney
Belted Kingfisher Articulation - Oxidation Method

Handling time: 24 hours
Soaking time: 34 days

1.  Carefully cut as much of the feathers, flesh, and muscle off without cutting into bone. Cuticle scissors work great because their small, curved, and sharp enough to cut through muscle and easy to maneuver around bone. Bird was placed in a 24 oz. container with 50/50 pure ammonia and water for 14 days.

2.  Bird was gently rinsed under cold tap water by splashing it with a hand not under full pressure, and not with hot or warm water. Bird was put back into the container with 17 % hydrogen peroxide for 10 days. The solution bubbles so if you'd like a top, poke some holes in the lid to let the oxygen escape. I kept a top on to keep the buoyant bird from sticking out of the solution. Make sure the container the bird is in is stable, preferably in another container or tub with paper towels at the bottom, to soak up bubble over and from the container from slipping around. Put in a spot it won't get knocked over.

3.  10 days later, took bird out of the solution to remove the head, legs, wings, eye rings, and tongue bones. Spent time de-fleshing and laid all the bones out on paper plates with wax coating. Bones may stick some so lift the bones up to loosen, especially the ones with extra flesh. To keep the neck bones in place and for re-positioning later I inserted 0.58-millimeter steel wire, cut to about 15 centimeters in length, into the vertebra. The wire reached down into the sternum firmly, but not with too much pressure.  The wire will be glued into place later.  A small excess of wire hanging out helps attach the head later on too. The body and feet (attached to legs) still needed more time in solution and were put back into a fresh batch of hydrogen peroxide for 10 more days.

4.  The bird's body should be puffy. The kingfisher had clear spots so I took it out and de-fleshed with cuticle scissors and dissection probes. The entire body was too delicate to place back into solution and didn't have very much flesh. Everything was placed on paper plates to dry (again lifting every so often to not stick, wax paper actually may have worked better). The wings and legs were placed on a small piece of cardboard, pinned along the sides using dissection pins (sewing pins or even toothpicks could work) to dry in their final positions. Remember, the idea is to keep the tissue near the joints attached so there's not too much gluing later. Don't over clean or over soak your bird.

Click on Photos to Enlarge

Amanda Martinez's Oxidation Method Experiment

Amanda Martinez from Albuquerque, New Mexico, did a dove skeleton and a house sparrow using the Oxidization Method. Both came out great. She soaked them in 50% household ammonia for 2 weeks. Then in 3% hydrogen peroxide, removing it every 3 or 4 days to trim off the bloated white flesh. A mouse and a small lizard failed.


​Yvonne Armbruster's Oxidation Method Experiment

​Jeremiah was a bullfrog!!!. . .Yvonne Armbruster from British Columbia, Canada, tried the Oxidization Method on a mouse and a bullfrog. She didn't use any ammonia. She soaked them in 3% hydrogen peroxide, changing the solution about 6 times over about 8 months. (I'm not sure why the peroxide didn't revert to maceration.) The mouse had a lot of clear tissue that remained dried between the bones, but the bullfrog turned out really well.


​Jacob Mishler's Oxidation Method Experiment

Jacob Mishler used the Oxidation Method on this three-toed sloth. This is what he had to say: First, I beetle-cleaned the skull. I cut as much flesh off the body as I could. I soaked [it] in about 50 percent ammonia. I left [it] in there for about 2 weeks. Then I put 1.5 liters of vol 40 solan peroxide and 2 gallons of water in a 5 gal bucket. 2 weeks later I removed and cut off as much of the white foamy flesh as I could. I wasn't happy with the results, so I put [it] back in the bucket with the old peroxide and water. I left it there for another 3 weeks. By then the peroxide was just water and started to macerate the body. Just enough to remove the extra flesh, but not enough to separate the joints. I put [it] in fresh water with some peroxide overnight to clean and disinfect.

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Starling Skeleton by Alex Richards Using the Oxidation Method

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