Molcajete
 

You don't wash the molcajete out except to rinse it after you use it and let
it air dry before you put it away. Never use soap as the lava stone picks
up the soap taste and odor and ruins it. It's like the old cast iron fry
pans. Once they are seasoned, you never have to wash them, just rinse and
air dry.

To season the molcajete, you rinse them and brush them with a hard brush.
Use scalding hot water. Let it air dry. Then take a 1/2 cup of white rice
and grind it down to powder. If the powder is not white, pour the rice out
and do it over again. Grind the rice until the powder is white. Then wipe
the powder out with a cotton cloth, rinse with cold water and let air dry.

Then take 1 tsp of salt, 1 tsp of peppercorns, 1/3 tsp of cumin seeds, 2
garlic cloves and 1/3 tsp of red pepper and grind to a pulp. Scrape the
paste out, rinse with cold water and let air dry. Your molcajete is ready
for use.

I find that they are fun, get better with age and works just as well as the
new blenders. You do have to work a little more though!