For him clinker pots are one of his various oeuvres of self-destructing “extreme pottery.”
Native red clay is mined on the artist’s property, and is inoculated with a material containing fossil carbon. This makes the clay expand like bread dough when it is fired to 2000 degrees F. The result is the appearance of an explosion frozen in time.
But there is another definition of “clinker pot” relating to a definition of the term “clinker” as a term for… “The incombustible residue, fused into an irregular lump, that remains after the combustion of coal.”
Some coals formed clinker pots; that is, they developed a solid mass of clinker in the middle of the fire pot. This formation usually took the form of a basin, or bowl; that is, the first clinker formed near the grate decreased the air supply to the coal above it and restricted its burning, while the ash of the coal that burned at its edges built up clinker around it.
P. Nicholls and W.A. Selvig
Clinker Formation as Related to the Fusibility of Coal Ash, 1932
Clinker Pots in this context are a container-shaped residue.