A kitchen must-have! Mortar and pestles have been used for thousands of years as the best way to crush and grind herbs and spices. Mortar and pestle allows you to release the flavors and oils in freshly ground spices which makes a big difference in the taste of the food. A stylish black marble mortar is also a kitchen decoration. Hand wash. Marble is a natural material, so product-specific differences may occur. Cleaning with a damp cloth or hand wash with a mild detergent.