The Hazel bowl from Muubs is handmade in terracotta, and burned over open fire. This gives the Hazel series a unique touch. The Hazel bowl from Muubs is handmade in terracotta, and burned over open fire. This gives the Hazel series a unique touch. The bowl has a practical size and can be used for everything from breakfast, serving or cooking your food. Before you use the bowls it is recommended that you rub each product, into cooking oil and put it in a medium warm oven for 30 minutes. The natural terracotta bowls must be cleaned with hot water and soap. Dishwasher is not recommended. The terracotta bowl can be used with the following heat sources: Gas burners or over campfire. The bowl is also ovenproof.