A dry bath involves using powder to dry up moisture and nice smells to cover up odor. Dry baths do not actually clean, think of a dry baths as equivalent to pouring baking soda on a wine spill. The baking soda dry’s it up and cuts down on the smell but does not actually clean the spill.
A full on bath with water and a nice clean shampoo will do wonders to get your dog clean and/or clean that spilled glass of wine. The times when the dry baths are ideal are when it is just too darn cold to get your dog wet, or when you only have a minute to clean things up.