Pottery Avenue’s Polish Stoneware, Mug makes for a fabulous addition to the collection for tea or coffee lovers. These Boleslawiec Pottery Stoneware mugs are made in a variety of just the right looks and sizes to let you enjoy the first cup of tea or flavored coffee while adding a little art in your kitchen. These handmade Polish Pottery pieces are safe for use with food. The mugs are safe in the dishwasher and microwave. Their unique glaze finish is lead and cadmium free.