A Dragon Bone Certificate is a certificate that is obtained by exchanging five dragon bones with Sidney Smith in Yanille. Dragon bone certificates are stackable and each one can be exchanged back for five dragon bones by talking to Sidney Smith. They are one of the most important items in the economy due to popularity of combat and slow pace of prayer training. Because dragon bones are not stackable and players can only trade twelve items per trade screen, they are often exchanged for certificates so that they can be traded easier and faster.