I too have been frustrated by carpet digging, although by having a few empty
closets available for my little fuzzie to get into, he doesn't seem to mind
the couple of closed doors too much.  What I have more trouble with is couch
digging..but that's another story.
 
I did notice though, in the July/August issue of Ferrets magazine there is
an ad for a product that is a plastic type of door guard.  It comes in sizes
to fit your door, and it's like a wide plastic strip that hugs the floor,
and has cut outs for the door frame on either side.  I would think maybe
that the fuzzbutts would just dig at the strip..but I could be wrong.  I'm
considering trying one to see if they work, they don't seem to be very
unattractive, and on the whole a good idea.
 
It's called Diplo-Mat, and they have a toll free 800 number.  I'm not
advertising for them, especially since I don't know if it really works yet,
but if you're interested and can't get the magazine, write me and I'll give
you the phone number and more information.
[Posted in FML issue 2347]