This article describes corrosion treatments available and seeks a suitable method for conserving large and small iron pieces of the salvaged hull of the Bremer Kogge. The corrosion treatment chosen is a variation of the fuming off of ammonium salts. Ammonium chlorides sublimate at relatively low temperatures. Temperature can be further reduced at low pressures. Inside a vacuum chamber iron objects are heated to 150 C by internal radiation as measured by a resistance thermometer at a pressure of under 0.5 Torr. Chlorides escape as a gas and are undetectable in smaller objects after one treatment.