According to Wikipedia: "In the German lowland of Schleswig-Holstein, a werewolf could be cured if one were to simply address it three times by its Christian name, while one Danish belief holds that simply scolding a werewolf will cure it. Conversion to Christianity is also a common method of removing werewolfism in the medieval period. A devotion to St. Hubert has also been cited as both cure for and protection from lycanthropes."
Apparently silver weaponry does not work - no one mentioned this remedy until 1935. So the best option may be a sharp "scolding" unless you know the creatures name.
Was the world more interesting back in 1998 or in 1944? http://news.bbc.co.uk/1/hi/uk/52289.stm