In July 1989, two 18th-century Swedish cast iron cannons were recovered from the Chandeleur Islands Cannon Site and then taken to Texas A & M University for the lengthy conservation processes. The scope of this article includes: 1) the field techniques used to identify the cannons in situ coupled with the innovative use of sacrificial zinc anodes that prevent the further deterioration of the corroded metal after the removal of some of the concretion layer underwater; 2) the transportation and storage of the cannons prior to conservation; 3) the mechanical cleaning and electrolytic reduction processes used to remove the concretion layer and chloride ions from the metal. This section also deals with the techniques needed to set up a simple electrolytic cell enabling one to treat corroded iron artifacts from a marine environment. Finally, 4) the techniques used to coat the surface of the cannons with a corrosion inhibitor and final sealant that will result in a lasting museum-quality exhibit.