How do you kill a werewolf?
Silver bullet, I believe. That’s the Hollywood version, anyway.
Rent “The Monster Squad” to learn how to deal with all types of monsters, and send them to a different dimension as well. 
I think you get one to say his name backwards. 
Silver bullet in the heart, according to Universal Studios. Although in THE WOLF MAN (1941) he was actually beaten to death with a silver-headed cane. And in THE HOUSE OF FRANKENSTEIN (1944) it was amended to “…fired by the woman he loves” to make a plot point. And in THE MALTESE BIPPY (1969) it had to be shot into the brain.
Why do you want to know?
In general, any silver weapon is supposed to work. AD&D has silver swords, spears, and arrows that work on things like wearwolves and vampires.
On a slightly related subject, What’s the best way to kill a vampire?
“Monsters got nards!!”