Many ferrets dig at the carpet [7.3], especially near doors that are
closed.  It's very difficult to teach them not to do it.  You're
better off protecting your carpet by putting down a piece of plastic
carpet protector from an office-supply store.  Chances are your ferret
will get bored with digging when she sees she's not getting anywhere,
though it might take a while for that to happen.  A carpet scrap or
sample from a carpet store might work, too, although your pet will be
able to shred it, so she might not give up as quickly.  For
out-of-the-way places, wire mesh can be nailed to the floor through
the carpet; be sure to protect any sharp corners or points.

Also be aware that ferrets like to dig in and possibly chew on
houseplants, and some common ones are quite poisonous.  Plants can be
protected from digging (but not chewing) by putting large rocks or
metal mesh over the tops of their pots.

Many ferrets like to rip the cloth on the bottom of a box spring and
climb into it, where they can easily get crushed or caught.  To
prevent that, try putting a fitted sheet on the bottom of the bed,
anchored in place with small nails or brads, or attach wire mesh or a
thin piece of wood to the underside of the box spring.  You may need
to drill air holes in the wood so the box spring can still compress.

Depending on how your cabinets and drawers are constructed and how
determined your ferrets are, you might be able to keep them closed
using strong tape, rubber bands around a pair of handles, a nail or
wooden dowel through the handles, or a strip of strong Velcro-type
tape on the door and frame.  Attaching eye hooks (screws with a ring
shape at the top) to the door and cabinet and putting a nail through
them both has worked for some people, and the latches with a pair of
rollers on one piece and a mushroom-shaped catch are said to be strong
enough for most ferrets.

Some kinds of child-proof locks also work very well, though others are
too weak or open wide enough to let a ferret through.  The magnetic
latch-and-key system works best for many people; they're available at
many hardware or childrens' stores, or from the Woodworker's Store
catalog (1-800-279-4441) or the Safety Zone catalog (1-800-999-3030).
The kind that lock around two handles at once, available from baby
stores, have also gotten a good report.

If your ferret scratches at the underside of your couch to get through
the fabric into the bottom, try taking off the couch's legs, if it has
them.  Heavy cloth or plywood stapled or nailed to the bottom can
work, too, though ferrets can often rip cloth loose.  Sometimes
ferrets try to get into the bottom or arms of the couch by burrowing
between the cushions and the back or sides.  This is much harder to
prevent, but some people have had good luck blocking the area with
cloth or wood, stapled, nailed, taped or sewn to the couch.  You can
also give in and remove the bottom fabric and lower stuffing from your
couch, putting a piece of plywood on the springs and the cushions on
that.  Then it doesn't matter as much if your ferrets get into the
bottom, as long as they don't get caught between the cushions and the
springs.

Many ferret owners find it simpler to give up and get a futon or a
"suspended" couch that doesn't have an inside in the first place.