You don’t have to clean every bone you find. If it has been out in the open, doesn’t have any soft tissue on it, and doesn’t smell, then it is pretty much clean – I still do a quick soak to disinfect, but it is rare to get diseases from any bones like this.

If the bone does smell, or has any flesh attached, then it needs to be handled with gloves until cleaned. How to clean them depends a lot on what state the bones are in when you find them.  It is ideal to leave the bones until have no soft tissue left, but that isn’t always possible – especially if it’s a small animal with small bones that might get lost.

Here is a quick guide to the methods I know of:

	Dry bones (with no tissue)	Mummified (or dried)	Skeleton (with soft tissue)	Rotting body	Fresh body
Leave above Ground
Bury
Dermestid Beetles
Hydrogen peroxide
Soak in Cold Water (Macerate)
Soak in Warm/Hot Water (with bio powder)
Hydrogen Peroxide
Boil
Bleach

This is a good method to clean

May or may not work, or may be very messy or smelly

Not a good method

Leave Above Ground

Dead bodies left on the surface rot down really well. The problem with leaving bodies in the open is that they can get taken away either by animals or humans. Foxes can move dead bodies over big distances, and pull them apart. To avoid this, leave them in a wire mesh, cage, or covered with an upturned plant pot weighted down.

Bury

Burying a dead body might seem obvious, but it’s not as good as leaving the bones above ground. If you need to bury it (perhaps you live in an area where you don’t have the space to leave it far enough that the smell is a problem) leave the body above ground for a day or so in warm weather so that flies can lay eggs so that the maggots which eat the flesh are buried along with the body.

• If you’re concerned about finding the bones again, you can use a wire mesh bag (or muslin for small bodies) to keep the bones together and stop animals from digging them up.
• Sand or overly saturated soil can actually preserve the body, so choose your burying spot accordingly!

The difficult part is knowing when to dig up your body. This depends on temperature, moisture, etc. and will vary according to your location.

Dermestid Beetles

Dermestid beetles are beetles that eat dead flesh. They are housed in special tanks, kept warm, and constantly fed with dead things. They are small – smaller than a fingernail – but they can eat a lot of flesh in a short time, leaving the bone nice and clean. They are excellent at leaving clean bone behind, though the flesh should be fresh for the best results.

• The beetles are great for very small animals because they leave just enough flesh for the skeleton still to be connected. For larger animals, a lot of the flesh should be removed so that the middle parts don’t start to rot by the time the beetles get to them.
• The temperature needs to be just right – if it’s too cold the beetles won’t eat, but if it’s too warm the flesh will decompose faster than they can eat it.
• Once the bones are clean of flesh, they may still need degreasing.

Macerate (cold water)

Rotting soft tissue in water is horrible and smelly. Not recommended if there are people nearby who can smell it. I have used soaking in cold water for when the body is skeletonized but there are still tendons attached. The water softens the tendons and makes them easier to cut.

• Remove as much flesh as you can manage.
• Put the rest in cold water to soak and soften any remaining tissue
• Change the water every few days until there’s no flesh remaining. You may need to manually clean the flesh off between soaks.

Warm Water (with bio powder)

Biological washing powder can be bought from supermarkets and is the type of powder used for cleaning clothes in a washing machine. It contains enzymes that break down fat and soft tissue. It is also very cheap.

• Add the powder to hot or warm water (not boiling water, see below)
• Leave bones in for usually a few days. (It helps if the water is kept warm for the duration. A slow cooker can be used for small enough bones)
• After you finish, rinse the bones really well (otherwise the enzymes will keep eating the bone).
• Then dry them using the method below.

Boil

NEVER PUT BONES IN BOILING WATER. This makes any fat present thinner, so it can soak inside the actual bone, and it will lock the fat inside the bone when it cools. The fat will come to the surface over time and make your bones look rubbish and horrible. If you have boiled bones already, try using biological washing powder to get rid of the fat.

Bleach

DO NOT CLEAN BONES WITH BLEACH. It damages the surface of the bone, and will soak in and continue to slowly eat away at them forever even after washing the bleach off. Use hydrogen peroxide instead.

Degreasing

Once your bones are clean of flesh, they will still need degreasing (removing the grease from within the bones).

• Soak your bones for 24 hours in a container of fresh water and dish soap.
• If lots of grease collects on the surface, change the water and repeat until no grease is present.

You can then move on to whitening or drying.

Hydrogen Peroxide

Hydrogen peroxide is a chemical which whitens the bone without damaging it. Whitening is not a necessary step when cleaning bones, but it does sanitize them and give them a clean-looking white finish. If you prefer the natural colour of bone but still would like to sanitize them, you can put them in low percentage peroxide for an hour or less.

Be careful with hydrogen peroxide – wear gloves and don’t get it on your skin. Depending on the strength you get, you can dilute it down with water to minimum 3%.

• Rinse the bones or skull with water to get out any dirt or bugs.
• Put the bones in a plastic container. (Peroxide breaks down with light, so a dark container is better)
• Pour peroxide over the bones. (Make sure all the bones are underneath with no air bubbles.)
• Cover the container loosely with a lid so that the peroxide can’t get out. 
• Then leave for 24 hours (or up to a week, depending on the state of your bones and how white you want them). Don’t get peroxide on antlers, because it looks rubbish. 
• When you take out the bones, rinse them well in a bucket of cold water (otherwise you will get white powder residue on the bones).

Peroxide will not dissolve soft tissue or flesh, but it can soften the tissue to make it easier to remove. It also sterilizes the bone. You can reuse the peroxide a few times. It seems to be reused better when it hasn’t been exposed to much air. If it’s warmer, the peroxide will work better. You will never end up with perfectly white bones if they are not properly degreased

Drying your bones

However you cleaned your bones, rinse them thoroughly, then they will need to dry. Note that wet bones often look dirty, but will dry much lighter. 

• Leave them air-dry for a few days.
• After that, put them on a tray covered in newspaper, and let them dry near a heater. DO NOT PUT THEM ON A HEATER OR A RADIATOR OR ANYTHING HOT BECAUSE THEY WILL CRACK.
• Leave the bones out for two or three days, even after they seem dry enough.
• If there is any dirt left, use a toothbrush to take it off. It should come off easily.

Bonus Tips:

Mummification: Mummified flesh has the water removed and the flesh feels like papier mache. Once the water is removed, it stops rotting. It feels fragile but it almost impossible to remove from bone. The best way I have found is to add water again and thoroughly soak it for a few days. THE SMELL WILL BE DISGUSTING. Then use another technique (burial is good) to get rid of the flesh.

Green Bones: First, soak in warm water with biological washing powder for a day or so, then leave in daylight. The green will usually go away. If it doesn’t, try repeating the process.