Someone recently asked advice for a ferret who was nipping.  As a kit
Mikette's specialty was nipping the ankles and wrists of visiting guests.
It made it hard to train her since she only did it to others.  I tried
lots of things, what finally worked was a water bottle.  I got an empty
spray bottle and filled it with water.When Mikette nipped I gave her a
spray and said "No Bite!".  After awhile she began to associate the
bottle with the water, then if she would sniff suspiciously near guests
ankles I would give a warning spray next to her and remind her "no bite".
This helped keep her on her best behavior.  Eventually the bottle came
out as a reminder when guests came (I always made sure she saw it).  Now
the bottle is put away and she doesn't attack the innocent (-:
 
Hope this helps someone!
Risa
[Posted in FML issue 4895]