How to use
A heavy, tip-resistant bowl or deep dish can be used. It should be slightly larger than the chinchilla. 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.
Offer the dust bath to your chinchilla at least twice a week, typically in the evening when they are getting most active. Usually 10 to 15 minutes is plenty of time for a chinchilla bath. 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.
Beaphar - Chinchilla Bathing Sand
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 use it as a litter box. If your chinchilla has dry, flaky skin or seems itchy, decrease the bathing time and frequency a bit.
You can 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. Can also be used by hamsters, gerbils and likes.