Polish Pottery Butter Keeper - Aztec Sky 3"H x 4"W Handmade and hand-painted in Poland. Keep butter fresh for several weeks without spoiling and without refrigeration! All of our Polish Pottery is safe for use in the microwave, dishwasher, and oven. Directions for use: Pack butter into top, fill bottom with 1/4" water. This forms the tight seal that allows the butter to stay fresh at room temperature!