My ferret used to dig carpet under the doors, especially the outside
door, until I tried this trick. I bought plastic mats - the kind you put
under rolling office chairs - from a large discount warehouse. These mats
are durable and have little spikes on the underside to hold them stationary
on carpeting. I cut them to fit under my doorways flush to the door frames.
They stay put because the spikes grab at the carpeting and the doors close
over them without a problem. People don't trip over them for the same reasons
they don't trip people in the office. They are impervious to ferret
claws. Mine gave up after about 2 minutes of trying.
[Posted in FML issue 1083]