mlm

There is an electrolytic recovery process that is applied to old iron cannonballs and other artifacts removed from the ground or sea. The idea is to electrically reduce (promote oxygen removal from FeO combinations?) the iron atoms. The result often looks great if the oxide is not too deep and has not "layered" in such leaves that it is hard to restore the physical structure of the item. 16th century iron anchors removed from the sea near Florida have sat as roadside attractions and crumbled in a few short years after having rested on the seabed in decent encapsulated condition for centuries. A luger exposed to air will also quickly crumble away.


Once treated this way, an iron object can be protected with a chemical to provide an oxygen barrier (like we use grease) or placed in an oxygen free environment -- also control humidity/temp.


That is how special iron objects can be treated in museums.