You also should learn how to clean the bones you will use in your practice of witchcraft. It is good to have in mind that they should be treated with respect. There are ways that you can have bones of animals. You can buy them but you do not know how they were acquired. You can also prepare them yourself. If you cannot have a bone of an animal, you also can have it by having your own. You should then have an animal which is already dead.
You can just put them on your rooftop to be exposed to the sun and decomposed naturally. You just have to wait for it. It can take months depending on the size of the animal and the type of animal. If you will use this method, make sure that you have a space for it so that your neighbor would not question you. It is best if you do not have a close neighbor. The other method is that you bury your animal and wait for it to decompose. It can take 3 months to 1 year.
It is best if you put it in a burlap sack so the bones are still in one place for easy retrieval. After it has decomposed, you can then soak it with tap water for days. replace the water daily until water is not murky. Scrub the remaining tissues and then submerged in hydrogen peroxide. This serves as sterilization and whitening of bones. After this, wash them again with water and they are now ready to use. Do not use bleach.