Daguerreotypes are rapidly tarnished by the formation of silver sulfide. The extremely thin surface and the faint coloration of daguerreotypes do not permit a treatment with soft brushes. Treatment in a hydrogen plasma to transform the silver sulfide into silver proved to be successful. After the plates were cleaned in a solvent bath, they were exposed to a hydrogen plasma for 5-15 minutes. A protection coating of Incralac was sprayed onto the plates.