A molcajete is a Mexican mortar and pestle tool that is used to grind spices or dried corn. Typically made of volcanic rock or stone, a molcajete is generally very rough in texture. This rough texture, with its countless nooks and crannies, causes the molcajete to absorb the smells of the foods and spices that were ground in it. It is this rough texture that would also absorb the soap and fragrances if you were to use them to clean one.
Rinse all of the food and spice particles out of the molcajete. To do this, simply run tap water over the surface of both the bowl and the pestle. Your goal here is to remove excess food particles that rinse off easily.
Plug up the kitchen sink, and place the molcajete in the sink. If your sink is easily scratched, place a dish towel on the bottom of the tub, to prevent the rough stone of the molcajete from scratching the sink's surface. Fill the sink with hot water. Allow the molcajete to sit in the hot water for approximately five minutes, to soften up any particles that are trapped in the craters.
Use the stiff-bristled brush to scrub the molcajete bowl and pestle. This will remove the stuck-on food, as well as any residue that might be left on the molcajete.
Drain the sink and rinse the molcajete in warm water.
Gently scrub the lemon on the surface of the bowl and pestle of the molcajete. Lemons have natural odor-absorbing properties, and this will help absorb the scent of any Mexican spices that were ground up in the molcajete. The lemon juice can be allowed to dry on the molcajete before putting it away.