From Bamboo Switch:
As the name suggests, a dry brush does not require water. Use a circular motion across your skin to lift dead skin cells and increase circulation. It can be used in the shower though (many customers love using this as a shower back scratcher!)
 
Dimensions: 3.5" inches wide 9" long
 
To clean the dry brush, we recommend the following: 1. Mix water with a little alcohol and add a few drops of tea tree oil 2. Spray the brush between uses 3. Allow to air dry between uses.
Completely wash it once/week by soaking in warm soapy water (we use a few drops of unscented Castile soap). Let it soak for 5-10 minutes and then shake out the excess water before letting the brush fully air dry.