Regular brushing is a great way to keep the coat in good condition and is especially useful when ferrets are shedding to minimize the amount of hair ingested by ferrets, thus preventing hairballs. Many ferrets are not keen on staying still long enough for brushing, so get in the habit of doing a very quick brushing frequently, rather than trying to get your ferret to sit still for a prolonged grooming session. Use a soft, short-bristled brush meant for cats or kittens, or try one of the newer rubber grooming tools which are great at quickly picking up loose hair from the coat (e.g. the Kong Zoom Groom)
Even with regular brushing, it is a good idea to give a hair ball preventative to your ferret regularly, especially when they are shedding. Preventatives are available in a a malt-flavored gel in a tube, and many ferrets learn to look a the preventatives as a treat.
Ferrets do tend to have waxy ears, and keeping them clean will help prevent problems and infections. Normally, their ear wax is light brown or reddish in color. Regular cleaning will help you spot a change in the amount or texture of ear wax which could indicate an infection or ear mites.
To clean the ears, get a mild ear cleaning solution from your vet or pet store - something safe for kittens should be okay for ferrets. My recommended method is to put a few drops in the ear, massage the ear for a bit, then let the ferret shake his/her head like crazy. This is great for dislodging wax, but it can be messy so you want to do this in an area that is easily cleaned such as the bathroom. A cotton-tipped swab moistened with the cleaner can be used to wipe out the external part of the ear. Never push a cotton swab into the ear canal! If your ferret is particularly squirmy, be extra cautious to avoid pushing wax down into the ear canal.
Note: Ear mites are quite common, and ear infections can occur as well. If your ferret has copious ear wax or discharge, dark brown or black wax, bad-smelling ears, or if your ferret is shaking his or her head, scratching at the ears, or tilting his or her head to the side, a trip to the vet is in order as soon as possible to rule out problems.
This is not the easiest part of the grooming routine, but getting in the habit can prevent dental problems down the road. Brushing the teeth is a good preventative measure and also gives you a chance to spot any developing problems early.
To make this easiest, use a toothbrush meant for cats that consists of a set of short bristles on a rubber tube that fits over your finger, or even just a piece of gauze wrapped around your finger. You can make it more agreeable but using a drop of your ferrets favorite liquid/gel vitamin supplement, but never use human toothpaste. Then simply wipe the teeth with the brush or gauze. Aim for doing the outside surfaces of the teeth and gums at first, paying particular attention to the gum line. As with many other grooming procedures, your ferret may object strenuously at first, but if you are patient and gently persist, slowly increasing the amount you do, chances are your ferret will come to accept tooth brushing as a part of his or her routine. Try to brush the teeth at least once a week.