Knife-milking was sticking a knife into the wall and catching in a bucket the milk that would spout from the end of the handle. The milk is magically coming from someone else cow. If one were to knife-milk too long, blood would start to come out and then cow would die.
Also known as Finn shot, this was the name given to projectiles supposedly causing sickness or sudden death. They were imagined to be sent in the form of bullets, insects, clouds or vapor, and so on. Many legends are concerned with the means by which one could protect oneself against this type of magic.
The salve was made of herbs, roots, and hallucinogens. They smeared it on an object or on themselves. Often imagination and masturbation were involved.
A specially potent and malevolent form of magic was referred to as seiðr. It was used to rob its victims of their sanity, their health, even their life, and generally to cause misfortune. This was a usually feminine form of magic that was also applied to the god Odin. Skills attributed to him are essentially the same as those identified in later tradition with the practitioners of magic, notably shape-changing, magic flight, and the use of spells to control the elements and conjure the dead.
When stealing from her neighbors, the witch supposedly had help from a familiar, variously referred to as a troll cat, milk rabbit, troll ball, puck, …
In general, people regarded the whirlwind as the manifestation of the witch’s or trollman’s power. It was believed that the witch traveled in the whirlwind to inflict harm on people and cattle or to steal hay.