Always use store-bought chinchilla dust for bathing. This is specifically made for chinchillas and this purpose. When the chinchillas roll in this dust, it penetrates their coat down to the skin and absorbs oil and dirt from the fur. Other powders or sand may look or feel similar, but just won't work the same way -- chinchilla dust is made to mimic what they would have access to in their native habitat. The dust should be at least a couple of inches deep in whatever container you use, so that the chinchilla can effectively roll in it. "Blue Cloud Chinchilla Dust" and "Blue Sparkle Chinchilla Dust" are two commonly recommended dusts, but just make sure you get one made specifically for chinchillas.
A heavy, tip-resistant bowl or deep dish can be used. It should be slightly larger than the chinchilla. Glass fish bowls or canisters can be used and work well. Also, a plastic house-type container with a rounded bottom can be purchased for this purpose. Fish bowls and the plastic house-type baths have the advantage of being fairly enclosed, which can help minimize the amount of dust flying around the room. If you watch this dust bath video, you can see an example of the plastic house-type dust bath in action, along with visualizing why it is nice to have an enclosed bath container. Place the bath in the cage every evening when the chinchillas are active. Sand will be sprayed everywhere, but this is part of having a chinchilla. The sand can be reused for a time, as long as any wastes are removed.
Giving the Bath - How Long, How Often?
The dust bath should only be made available to the chinchilla intermittently, rather than left in the cage indefinitely. Too much bathing can dry the skin, and if the dust is left in the cage chinchillas will often sit in the bath and.or use it as a litter box. Offer the dust bath to your chinchilla at least twice a week, typically in the evening when they are getting most active. Twice a week is usually sufficient, though you can offer the bath more frequently if your chinchilla's fur starts to look rough or feels damp or oily. In humid weather, baths should be offered more frequently. Usually 10 to 15 minutes is plenty of time for a chinchilla bath. If your chinchilla has dry, flaky skin or seems itchy, decrease the bathing time and frequency a bit.
Re-Using Chinchilla Dust
It is fine to re-use the dust for several baths. Make sure to scoop out any waste when the chinchilla is done each bath. If the dust starts to look clumpy or dirty, discard and use fresh dust.
The Dust is Everywhere!
Unfortunately, this is an inevitable part of chinchilla ownership. Using a covered bath can help, but your chinchilla will still shake and groom after a dust bath, resulting in a fine layer of dust on everything around your chinchilla. Invest in a good duster and remind yourself that you are being a good chinchilla owner by providing regular baths!