Dear C. Cook,
I am not sure if the black pottery from Oaxaca has lead in it, but
there is a method to determine if it does. You will need to allow at
least a cupful of distilled water to remain in the vessel for a
period of 24 hours. If the GLAZE has any lead in it, the water will
absorb some of the lead which can be determined by a laboratory. But
this is if the pottery is glazed. If your pottery is POLISHED I am
unsure if the above method can be used. Joanne Reiter.