Ferrets can be trained to use a litter pan, but unlike cats, they
don't take to it automatically.  To litter-train your ferret, start
him out in a small area, perhaps his cage [5.4], and expand his space
gradually as he becomes better trained.  If it's a big cage, you might
need to block off part of it at first.

Fasten the litter pan down so it can't be tipped over.  Keep a little
dirty litter in it at first, to mark it as a bathroom and to deter him
from digging in it [7.3].  Don't let it get too dirty, though; some
ferrets can be pretty finicky about their pans.  Likewise, ferrets and
cats often don't like to share pans with each other.  Most ferrets
won't mess up their beds or food, so put towels or food bowls in all
the non-litter corners until your ferret is used to making the effort
to find a pan.  Bedding that has been slept in a few times and smells
like sleeping ferret will be even better than clean bedding for
convincing a ferret that a corner is a bedroom instead of a bathroom.

Ferrets generally use their pans within fifteen minutes of waking up,
so make sure yours uses the pan before you let him out, or put him
back in the cage five or ten minutes after you wake him up to come
play.  When he's out running around for playtime, keep a close eye on
him, and put him in his litter pan every half hour or so, or whenever
you see him "pick up a magazine and start to back into a corner" (as
one FML subscriber put it).

Whenever your ferret uses a litterpan, whether you had to carry him to
it or not, give him lots of praise and a little treat [6.3] right away.
Ferrets will do almost anything for treats, and they're fast learners.
Within a few days, your ferret will probably be faking using the pan,
just to get out of the cage or get a treat.  That's okay; at least it
reinforces the right idea.

Positive reinforcement (treats and praise) are usually much more
effective than any punishment, but if you need one, use a firm "No!"
and cage time.  Rubbing the ferret's nose in his mess won't do any
good.  He can't connect it to it being in the wrong place, and ferrets
sniff their litter pans anyway.  As with all training, consistency and
immediacy are crucial.  Scolding a ferret for a mistake that's hours
or even a few minutes old probably won't help a bit.

If your ferret's favorite corner isn't yours, you have a few choices.
could put a pan (or newspaper, if it's a tight spot) in it; ferrets
have short legs and attention spans, so you'll probably need several
pans around your home anyway.  Otherwise, try putting a crumpled towel
or a food bowl in the well-cleaned corner, making it look more like a
bedroom or kitchen than a latrine.

"Accident" corners should be cleaned very well with vinegar, diluted
bleach, or another bad-smelling disinfectant (don't let your ferret
onto it 'till it dries!), specifically so they don't continue to smell
like ferret bathrooms but also as a general deterrent.  For the same
reason, you probably shouldn't clean litter pans with bleach,
certainly not the same one you're using as a deterrent elsewhere.
Urine which has soaked into wood will still smell like a bathroom to a
ferret even when you can't tell, so be sure to clean it very well,
perhaps with Simple Green or a pet odor remover, and consider covering
wooden cage floors with linoleum or polyurethane.

Although almost every ferret can be trained to use a litter pan, there
is individual variation.  Ferrets just aren't as diligent about their
pans as most cats, so there will be an occasional accident.  Even
well-trained ferrets tend to lose track of their litter pans when
they're particularly frightened or excited, or if they're in a new
house or room.  In general you can expect at least a 90% "hit" rate,
though some ferrets just don't catch on as well and some do
considerably better.  At least ferrets are small, so their accidents
are pretty easy to clean up.

Finally, if your ferret seems to have completely forgotten all about
litter pans, you might need to retrain him by confining him to a
smaller area or even a cage for a week or so and gradually expanding
his space as he catches on again.