Chinchillas, having up to 60 hairs growing out of each hair follicle (humans have one), have one of the densest, finest coats in the animal kingdom.
Wild chinchillas live high up in the mountains and have ample access to very fine, powdery sand in which to bathe.
It is absolutely essential that pet chinchillas be allowed to bathe in proper chinchilla dust daily to keep their coats in good condition.
If your chinchilla has any odour at all, or if you can see the separate hairs of the coat instead of a velvety "plush" look, your chin is dirty and needs to bath.
NEVER bath a chinchilla in water!!! Coarser sands such as building sand are also pointless to use for bathing.
The very fine, special dust needed actually absorbs oil and dirt from the hair coat.
Tenrecs also enjoy bathing in this sand.