Paper was invented in China, traditionally by court official Ts’ai Lun in 105 AD. It was actually invented around 3 centuries earlier, but not used for writing until the 1st century AD. Up until that point, characters had been painted onto wood or bamboo, or for the very wealthy onto silk. The wood was cut into strips 1 character wide. Multiple strips could be tied together so they could be fastened into a roll, or alternatively a hole was put in the top of each strip and a cord threaded through. The roll or bundle could be tied in such a way that the text faced inwards, with clay to secure the bundle and a seal applied to ensure the content was not read by unauthorised people. Tags were used to identify the contents of archived material.
Such bundles would of course burn well.
This information is from Michael Loewe: Everyday Life in Imperial China During the Han Period