Empty out the grill to remove any ashes or old charcoal. Fill the bottom of the grill with a pile of fresh coals. Soak the charcoal with lighter fluid and light the coals.
Replace the cooking grid into the grill. Place green pottery on the grid to preheat it. Use pots with a uniform thickness, avoiding those with thick bottoms or thin walls.
Put on protective gloves. Remove the pots and set them aside when the coals develop white ash on the edges. Remove the cooking grid and spread the coals around into a smooth layer.
Nestle the warmed pots into the coals. Add bits of hardwood to create extra smoke markings on the outside of the pots.
Close the lid on the grill, leaving a space open to allow air to circulate. This will increase the temperature inside the grill. Allow the pots to fire for about 30 minutes.
Open the grill and check the pots to see if they are done. Tap each pot to listen for a ringing sound, or try to scratch the surface with a fingernail. If the pots ring or cannot be easily scratched, they are done.
Remove the pots and set them in a safe place to cool.