As every ferret owner knows, our little friends love to get into
trouble.  Whether your ferrets live in a cage when you're not around
or are free all the time, whether they live in a single room or have
the run of the house, the first line of defense, both for your ferrets
and for your possessions, is a well-ferretproofed home.

Ferrets love to worm their way into any little hole (as small as 2 X 2
inches, or smaller for kits and some adults), which can be very bad if
the hole in question is under or behind a refrigerator or other
appliance (with exposed wires, fans, insulation, and other dangers),
into a wall, or outside.  Crawl around on your stomach to look for
holes near the floor and under cabinets, especially in the kitchen and
laundry area.  Even holes inside cabinets (which are particularly
common in apartments, where plumbers are often rather sloppy) should
be blocked, just in case.

Ferrets can open cabinets and drawers, which can be dangerous or just
annoying depending on what's inside them [5.2].  Also watch out for
heaters or furnace ducts.  You can block openings with wood or wire
mesh; be sure to leave ventilation around appliances.  For doorways,
try a smooth piece of plywood or Plexiglas slid into slots attached to
the sides of the doorway.  Recliners and sofa-beds are very dangerous;
many ferrets have gotten crushed in the levers and springs underneath.
They're difficult to ferretproof, except by putting them in a
forbidden room.  Even regular couches and beds [5.2] can be dangerous
if the ferret digs or crawls his way into the springs or stuffing.

Next, look around the area your ferret will be playing.  Remove
anything spongy from reach, and put fragile items out of the way.
Keep in mind that many ferrets are good climbers and jumpers, and they
excel at finding complicated routes to places you never thought they
could reach.  They can get onto a sofa, into a trash can, onto the
third shelf of a set of bookcases, into a bathtub or toilet (from
which they might not be able to jump out), and into the opening on the
back of a stereo speaker.  They can also open cabinets and drawers,
unzip backpacks, and climb up drawers from underneath or behind to get
onto the desk or kitchen counter.

Apart from obvious dangers such as bottles of household cleaners,
which ferrets do sometimes like to drink, be particularly careful
with sponges, erasers, shoe insoles, foam earplugs, Silly Putty,
foam rubber (even inside a cushion or mattress), styrofoam,
insulation, rubber door stoppers, and anything else spongy or springy.
Ferrets love to chew on that kind of thing, and swallowed bits can
cause intestinal blockages [11.1].  For some reason, many ferrets
like to eat soap [8.7], so you'll have to keep that away from them.
(A little lick won't hurt your ferret, just give her a bit of
diarrhea, but large amounts can be a problem.)  Human foods should
also be kept out of reach, since even the ones which aren't dangerous
to ferrets aren't good for them in large quantities.

Be careful about full bathtubs, where your ferret might possibly
drown, and consider keeping your toilet lid closed for the same
reason.  Buckets of water, paint, etc. can also be drowning or
poisoning hazards, or might just be tipped over.  Toilet paper and
paper towel rolls are a problem because ferrets get their heads stuck
in them and can choke or suffocate, and if you let your ferret play
with plastic bags, you may want to cut off the handles and cut a slit
in the bottom.

Certain ferrets may also have special ferretproofing needs; for
example, some like to eat paper, cloth, or plastic bags, which can
easily cause a life-threatening intestinal blockage.  A few ferrets
like to chew on electrical cords or plants, and some common plants
are quite poisonous.  Liberal application of Bitter Apple paste [5.3]
to the cord or plant can help persuade your pet to stop gnawing on it.

Finally, once your home is done, it's important to keep it safe.
Watch your ferret's toys to make sure they're not beginning to crack
or break apart, and keep in mind that you can be dangerous to your
ferret, too.  Always double-check your dishwasher, refrigerator,
clothes washer and dryer (even top-loading models) before closing them
or turning them on, and watch where you sit and walk: that chair,
throw rug, or pile of laundry might be hiding a napping ferret.