When smiths make their goods some shards or fragments are left over I am sure. Now take those shards or fragments and ground them out into a chalk or powder if you will, and put in a baggy.
Now when one see's a werewolf they can take said baggy and throw it at them; the contents - the powder - exploding into a cloud which the werewolf would inhale. The powder gets in its throat, nose, eyes, etc. This then drives the werewolf crazy a few turns as it is so focused on getting that junk out of its throat, nose, eyes, whatever that it does not even care about you - until it gets it out that is.
That is my explanation for my idea of a "Silver Powder" bag. Something that gets werewolves off you long enough for you to get lost, or get ready. Sounded neat to me so thought I'd post it here.