After drying for more than 5 months using Japanese materials, this vessel is hand grinded. The urethane paint used to paint is the same safe and durable paint used in all elementary schools in Odawara City. Because it is natural wood, the same wood grain is unmatched, and the same material is represented as the material, so there are small knots and spots that do not interfere with use. You can use detergent but gently wash it with a soft sponge. Please do not use too much to soak in water or hot water. Since it is made of natural wood, please do not pour hot water directly or disinfect boiling. Not microwave or dishwasher safe.