Cassia is more widely used because it is slightly easier to harvest than true cinnamon and therefore is cheaper to produce. Both cinnamon and cassia barks are stripped from trees and dried, except that cinnamon undergoes and extra refining step of having the outer bark rotted off, leaving the delicate inner bark behind. Both the inner and outer bark are left on cassia quills, and as a result it is a coarser product. The U.S. Federal Trade Commission says that both can be sold as cinnamon.