Though the glass (borosilicate) jars can be run through a gentle dishwasher setting, it is best to wash the jars with warm soapy water by hand.If you find starter has stuck to the inside or outside of the jar, soak in warm water for awhile before attempting to clean. Rinse well, so that no soap residue remains (any detergent remaining in the jar can be harmful to the microbes in your starter culture).