Stone mortar and pestle cleaning is a simple process that can be completed in a few minutes. First, remove the stone pestle from its stand. Next, unscrew the top of the mortar and pestle. Place the pestle on an angle so that the bristles point down, and use a plunger to suction onto one end of the bristles and pull until all of the liquid has been drawn up into the pestle. Turn off the plunger and release the pestle from its position on top of the mortar. Remove any remaining liquid with a paper towel or cloth.