The restoration and conservation of archaeological metal objects using hydrogen low-pressure plasma system. The equipment for and the principle of the method for the reduction of iron oxides and removal of chlorides are described. X-ray diffraction curves of samples before during and after treatment show the reduction of the material to iron. Changes in chloride content are also illustrated with diffraction curves. Treatment of silver objects is discussed next. The changes in agcl content as a function of time is shown graphically. A Roman silver beaker before and after plasma reduction is illustrated, together with two cross-sections, before and after, showing the conversion of corrosion products into silver. Finally the possibility of using the technique on corroded bronzes is considered. References.