Please note that one should never use soap or dishwasher liquids to clean the earthenware, as these clay pots and pans are porous, tiny bits of soap could get stuck in them, and upon using Earthenware for your next meal, your food may get affected.
To clean Earthenware, pour in hot water and gently scrub it with a brush. In some cases, you might be left with some stubborn bits that gets left behind, to get rid of them just thrown in some salt or baking soda and clean it with a brush or a sponge.
In the worst case scenario, if you are still left with stains, pour some hot water and add 2-3 tablespoon of baking soda to it and let it overnight, next morning the food remains will come off easily.
The unglazed Clay Pots and Pans will require seasoning from time to time, either you can get a new one or if you want to keep the existing one, you can soak it in clean water for 3-4 hours, and after drying the pot, rub it with garlic and then spread some olive oil all over the Earthenware.
Once the pot or the pan is oiled up, fill it with water, place it in the middle rack of the over (cold/non-pre heated) and crank up the temperature to 225 degrees for 2-3 hours. You can also heat up on a stove.