What material was used for writing in Sumera?

In Ancient Mesopotamia, cuneiform writing became widespread. Wet clay tablets were marked with a sharpened stick. The prints were wedge-shaped. Then the tablets were dried in the sun or burned. The sun-dried plaques could be corrected. For this, the plate was moistened with water and the necessary corrections were made. This was necessary in the case when the debtor slave worked off part of the debt. Clay tablets were put into boxes in order and content. They were clay books. Cuneiform was also used in Ancient Egypt because the production of papyrus was long and expensive, and clay was quite cheap and durable.