Our ferret used to dig up the carpet by our closet doors, so we bought
some plastic from Lowe's which is usually laid down in hallways to protect
carpet.  I measured the outline of the door frame and cut the plastic.  It
is positioned so half of the plastic is on one side of the door and half on
the other side.  I was pretty doubtful it would work, but Boo started to
dig on the plastic and after two minutes without making any progress has
never dug by the doors again.
 
Michael
[Posted in FML issue 3378]