Casa Maria 8.5 in. Natural Stone Double Sided Mortar and Pestle. Since it is made of natural, unpolished granite, it contains residual stone dust and loose grit from the manufacturing process.Before you use it for the first time, you must cure and season it to prevent grit from getting into your food.How to Season Your New Mortar and PestleInitial Rinse: Rinse both the mortar and pestle thoroughly under warm water. Do not use dish soap, as the porous stone will absorb it and make your food taste like soap. Use a clean brush or scouring pad to scrub away loose surface dust, then let it dry completely