Summarize this article:

Watch to see where your ferret goes to the restroom when in the cage. Place the litter box in this same location. Then, put a few fresh droppings into the box, so that it smells like a restroom for your ferret. Most ferrets will quickly start using the box. If your ferret refuses to use the box, then experiment with changing out the litter to another type of plant fiber. A litterbox trained ferret will usually only have a few accidents, which will lessen overall odors. Use a scoop to pick out the soiled pelleted paper or granules from your ferret's box. Leave a few droppings behind each time so that your ferret will continue to use the box consistently. When the box seems low on paper or granules add some fresh ones. Don't move the litterbox after cleaning it or your ferret might stop using it. Only use pelleted paper or granules for your ferret's box. Clay pellets are dangerous for ferrets if ingested. Remove the litter box, toys, and any other items from your ferret's cage and take it outside. Use dish soap and water to scrub the cage down. Let it dry outside and use this time to wipe down the box and toys. Coated wire cages have a tendency to stay cleaner than wooden ones. The wood often absorbs odors over time. It's also important to clean out your ferret's cage if stale food, for example, gets attached to the surface. Your ferret probably loves its sleep sack or hammock. However, the fabric can accumulate odors over just a few days and become quite stinky. Take it out of the cage and follow the fabric's directions for cleaning. You'll need to use hot water and unscented laundry detergent to clean most ferret fabrics. This is especially important since some ferrets are allergic to scented cleaners. When your ferret runs around your home playing, they are likely transferring oils from their body on to your furniture, rugs, carpet, and other furnishings. This means that their musky scent can linger on items for an extended period of time unless cleaned away. Mopping your floor and vacuuming can help to pull up and remove these odors. It's also sometimes easiest to limit your ferret to a couple of animal-proofed rooms that you clean regularly. Powdered or airborne deodorizers can harm your ferret's lungs or skin due to their chemical composition. Instead, position a solid deodorizing item in a ferret-proof area of the room, such as high up on a bookshelf. If you can find a deodorizing product made from natural ingredients, such as lemons, that is even better.
Train your ferret to use the litter box. Clean the litter box daily. Scrub out your ferret's cage once a month. Launder your ferret's bedding on a weekly basis. Dust and vacuum your home weekly. Place a solid odor-reducing product out of your ferret's reach.