Potashes are an important source of potassium. Synonyms for this term include potash, potassium carbonate, and pearlash. Potash is the most commonly used synonym for potashes. It is a key ingredient in fertilizers and can also be used in the production of glass, soap, and pottery. Potassium carbonate is another term used to refer to the alkaline salts that remain after the combustion of plant materials. Pearlash is a term that was used in the past to refer to the white residue left behind after the burning of wood or other plant materials. These synonyms are all commonly used in industries that rely heavily on the use of potassium.