What does the Large Glass Tea Washer used for? The tea washer is used for sterilizing and cleaning the tea cups tools by boiled water. In the tea ceremony, the tea cups must be cleaned up before use to drink tea. At first, put all the gongfu tea cups in the the tea washer, and pour the boiled water into the tea washer to warm and wash the tea cups. Then, the tea cups can be used for drink tea so that you could get the best flavor of the tea.