It started as an unidentifiable mass and ended up being a rather rewarding conservation project. A heavily concreted lump of metal was found at an 18th-19th century site located on the Aberdeen Proving Ground, a United States Army facility located near Aberdeen, Maryland, in Harford County. The object was taken to the MAC Lab (along with the other artifacts from the site) and x-rayed as the first step in the conservation treatment process. The x-ray showed that the metal lump was an iron chain solidly encased in corrosion material. Conservator Cait Shaffer undertook the labor of freeing the chain. After 40 treatment hours, each link of the chain was separated from the concretion and the artifact was fully conserved. According to Cait, freeing the chain links was time consuming but quite satisfying.
The concreted iron chain before treatment.
X-ray of chain.
Chain during conservation treatment.
Completed!
Courtesy U.S. Army Garrison, Aberdeen Proving Ground
Maryland History by the Object 