The mortar and pestle is what many experienced cooks reach for first when they need to grind and mix spices and herbs. The tradition of using these tools reaches back to the dawn of humanity when the first cooks beat their food between a flat rock -- the mortar -- and a smaller rock -- the pestle. Today's rounded bowls come in a variety of materials, including lava, granite and marble, which replace the original rocks. Natural mortars and pestles may have to be cured, or seasoned, to remove any rough areas that will crumble and get into the food.
Place newspaper over a table and use as a workspace to catch the small pieces that come off the mortar and pestle.
Rub the interior of the bowl and the grinding end of the pestle gently with the coarse sandpaper. Follow with fine sandpaper, continuing to rub until the bowl and the pestle feel smooth to the touch.
Wipe the bowl and the pestle with a soft cloth.
Place enough uncooked white rice into the bowl to just cover the bottom. Grind the rice with the pestle until it is powdery. If the rice remains white, the mortar and pestle are smooth enough to use. If the rice appears gray, toss it out and add more to grind. Continue to grind rice the same way until a batch remains completely white.
Clean the mortar and pestle with soap and water and let dry.
Add a few cloves of garlic, 1 tsp. of salt and sugar, and some peppercorns to the mortar. Grind until everything is a smooth paste. Rub the paste against the interior of the bowl and let set for 30 to 60 minutes. Wash the mortar and pestle again. It is ready for regular use.