Iron artifacts removed from shipwrecks are often encrusted with a hard calcareous concretion. If the artifact is partially or completely oxidized, it is possible to break it open, clean out the decomposed material, then fill the cavity with an epoxy compound known by the trade name HySol. A partially degraded ship's fastener was treated at the Florida Research and Conservation Laboratory in this manner, then subjected to electrolytic reduction. After completion of the treatment, a composite HySol casting and wrought iron artifact remained which accurately represents the original fastener.