earthenware pot ash

Quick answer：

The phrase 'earthenware pot ash' likely refers to the residue left after the ashing of an earthenware pot. This could be a term used in archaeology to describe artifacts, or in chemistry to describe the ashing process used to analyze the contents of an earthenware pot. Earthenware is a type of ceramic made from clay, and ashing is a method used to remove organic material from a sample, leaving behind inorganic minerals.