Water, oxygen, and chlorides are responsible for the corrosion of iron. Because it is very difficult to eliminate all moisture and oxygen from a museum display case, excavated iron objects on public display can only be protected from active corrosion by the removal of intemal chlorides. The authors studied the effectiveness of a number of methods of chloride removal (including washing in distilled water, intensive washing in deionized water, intensive washing preceded by a formic acid bath, alkaline sulfate solution bath preceded by a formic acid bath) on excavated Roman nails. One aspect of this study was the assessment of the distribution of chlorides in the core and corroded outer layers. They found that the alkaline sulfite process removed twice as much chloride as any other process and was the only process which did not endanger the metal. See also AATA 18-1697 for related study and 20-957 for reference to book. -- AATA