First up, let's get the names of the two pieces clear. There are two pieces to the toolset we call mortar and pestle: mortar is the bowl and the club-like tool is called a pestle. The word for the savoury, herby green sauce known as Pesto, comes from the pestle that was originally used to make that delicious sauce. Of course, now with blenders and food processors, the mortar and pestle toolset is rarely used to make pesto.
For those that love to approach cooking from an artisanal perspective, mortar and pestle units are available in sizes from miniature to giant, and in several different materials. I prefer ceramic for grinding garlic and fresh herbs. Anyone who uses a ceramic mortar to grind fresh turmeric knows that everything ends up being stained a bright yellow-orange colour. A quick swish with a quarter of a fresh lemon restores both the bowl and pestle to their pristine white.
For grinding nuts and seeds, I turn to my stone or cast iron mortar and pestle because the heavier weight keeps the bowl from moving around on the work surface as I grind. I season all of my cast iron utensils with a light application of cooking oil to keep them from rusting. After using my cast iron mortar and pestle, clean-up is easy. I wipe the inside of the bowl and the pestle with a warm, damp cloth and re-apply a light coat of oil.
Muddling mint with sugar and other fragrant herbs for cocktails is easy using a ceramic mortar and pestle. Try bruising 2 fresh mint sprigs with 1 tablespoon granulated sugar in the mortar and pestle–you don't need to mash, just thump the mint one or two times to release the essential oil into the sugar. Your Cuba Libra cocktails will have a mixologist's flair.