Archaeologic objects of metal, found underground, are often exposed to decay especially those made of bronze or iron. The article deals with the conservation of such metal findings, and the method of clearing such objects from rust. As the removal of rust up to the metallic core always means very hard wear to the findings, the process of dissolving the harmful saline deposits from the coating of rust resp. from the iron itself will prove to be more satisfying. Mr. Kentamaa has introduced an electrolytical desalting method for iron at the National Museum in Helsinki, which is operated on a sheet lead anode and a sheet zinc cathode. This method has now been improved by the author, and was linked with a washing process. An instrument, specially constructed for this purpose permits the treatment of several objects at a time, and working without supervision, will stop running automatically after the desalting of the findings. Therefore, injuries to the archaeological findings are avoided to the greatest possible extent.