Verdigris is

Copper is not poisonous in the metallic state, but some of its salts are poisonous. The two most commonly known salts are copper sulphate or blue vitriol and the subacetate or verdigris.Copper subacetate is a bluish green salt formed by the action of vegetable acids on copper cooking vessels that are not properly tinned.Krishan Vij textbook of forensic medicine and toxicology 5e pg: 569