Some notes about the use of Beaver (Castor Fiber) in Trolldom:

The most used part of the beaver comes from two glands located in the rear of the beaver. They contain a yellow strong smelling liquid. The liquid is called Castoreum and has a long medical history in Sweden. It occurs in all kinds of formulas in which various cramps or insanity is involved. For this reason it is also used against all kinds of destroyed conditions.

The second most common thing in use is the teeth of the beaver. The virtue or idea in use is that something removed with a beavers tooth will never grow back. For this reason axes were rubbed with the tooth when taking down unwanted bushes or they are used to “draw” around absesses or other unwanted bodily growths. Usually accompanied by a formula such as this from 1720:

“Oxel, vara vad du kan, så skriver jag med denna bjurtand! Du ska mås I hull, som döder man i mull”

In English:
”Oxel [a skin disease] be what you can, and I´ll write with this beaver tooth! You shall be consumed and disappear from flesh, as a dead man in the ground. “

In modern trolldom the teeth are used along the same lines to hinder the growth of everything from hatred or animosity to unwanted love and similar things.

And as a final nore:
In the old days the beaver was nearly extint in Sweden, but luckily it has regain its strenght in modern days. I don´t think any animal should ever be killled solely for its use in magic.