A mortar stuck to the wall. If you look carefully at the mortar you will see what looks to be the orange peel surface of salt glaze. When I first went to Koh Kred I was convinced that they were salting their kilns. I asked how much salt. My Thai was rotten. They said, "salt does not burn". I assumed it was a secret. I should have known better but a few months later on a return visit with Kurt Weiser I saw them unloading Palm Fronds as fuel. I thought, "Of maybe they are all full of salt". They are full of potassium and some sodium.