Exterior resolvers are acrid substances (foods or herbs) which relieve congestion at the surface of the body, expelling externally contracted pathogens such as wind heat and wind cold. The acrid, or pungent taste, moves and disperses. Exterior resolvers move the Qi by activating the Yang Qi of the Kidneys. In doing so, prolonged and inappropriate usage wastes the Jing. The most commonly used and familiar surface reliever is coffee. Even decaffeinated coffee (it should be clear by now that one chemical compound does not explain the entire nature of a substance) acts as a surface reliever, although caffeine itself does this as well. Regular use of coffee wastes the Jing, dries the Blood, and blocks the flow of Liver Qi. Its regular consumption produces more imbalance than any other food item I am aware of.