In natural glazing, or ash glazing, natural plant materials like longan shells or mung beans are burnt to ashes, which are sprinkled onto glaze before firing. To Hsieh, who specialized in the chemistry of glaze, even soy sauce could serve as glaze ingredient. When using glaze, he was like a magician pulling money from thin air: the process was simple but awe-inspiring.
「自然釉」又稱「灰釉」，就是將龍眼殼、綠豆等天然植物燒成灰後，灑在釉藥上再入窯燒製，對專修陶瓷化工、連醬油都可以當釉藥的謝嘉亨而言，運用釉藥就像魔術師表演空中取錢一樣輕而易舉。