This Anglo-Saxon or early medieval copper alloy hanging bowl was discovered by a metal detectorist, lying upside down in the earth and containing several human bones.
Having been recorded by the Portable Antiquities Finds Liaison Officer for Hampshire, it was purchased by the Museums Service and transferred to the archaeology conservation laboratory for treatment.
Since the bones were already out of their original positions, a mini excavation (often performed if a vessel holds earth and potentially other objects) was not performed. Instead, the bones were gently washed in water with a soft bristled brush and slowly air dried, and the bowl was mechanically cleaned before stabilisation and the application of a protective coating.
The surface of the bowl was almost completely covered in a thin layer of sandy, gravely soil, which had dried solid. Initial tests and microscope examination showed that the smooth green patina of the bowl was easily scratched, and therefore removal of the dry soil with a scalpel was not possible. Although water would not normally be introduced to a metal object post excavation, it was decided that in this case a little water run onto the soil encrustations with a paintbrush would soften them enough to allow them to be easily removed with handtools.
Once the surface had been fully cleaned, the three holes around the rim for the suspension of the bowl could easily be seen. Removing the soil also revealed many tiny pits of bright green and powdery active corrosion, or ‘bronze disease’, which erupt rapidly, scar the surface of, and eventually eat through copper alloy objects. A more mysterious find was the four scratched areas on the base of the bowl: Though they appear recent, and have been intentionally made, they were beneath a substantial layer of corrosion and dirt.
The powdery pits of active corrosion were excavated with a scalpel, under a microscope, before a stabilising agent was applied – this will halt the development of further corrosion. Finally, a clear, protective lacquer was applied, incorporating a matting agent to prevent the creation of an overly shiny surface.