Neglecting corrosion, Oddy and later Holze interpreted golden chalcopyrite layers on Roman bronzes as cases of intentional pseudogilding and referred to recipes in the Papyrus Leiden X and the Mappae Clavicula. But these are far from clear and not other applicable methods seem to be described in the (al)chemical literature. Because such layers are formed under definite reducing conditions by the action of sulphate reducing bacteria, corrosion seems more likely, although a scientific distinction might be impossible. -- SCMRE