Mechanical Cleaning and Artifact Indentification
The soil surrounding the artifacts contains clay minerals, feldspars and quartz and has a high organic concentration. This soil when mixed with ground water makes a paste-like soil matrix which adheres to the object. Before artifacts can be identified, this soil matrix must be removed.
Upon excavation, objects are brought to the laboratory for mechanical cleaning. Stable ceramics, glass, wood, pipe fragments, roof slates and iron are first sorted by material. Objects of similar material are washed under a gentle flow of water to remove surface dirt. Sometimes stencil brushes are used. Artifacts are then identified, catalogued and conserved.
Detergents are generally not used for cleaning artifacts because of potential damage and/or contamination (for the purpose of scientific examination) of the object. Occasionally chemicals are needed to remove dirt and staining. This requires the expertise of a conservator who understands chemical reactions and can control the chemical cleaning process.
During the mechanical cleaning stage only loose dirt adhering to the object's surface is removed. Any material which has been corroded to an object's surface must be x-radiographed prior to treatment. X-radiography used for metal objects produces images which allow the conservator and archaeologist to see the original surface and the internal condition of the artifacts. This not only helps to identify objects but also to predict artifact condition.
The conservation laboratory is not just a space for processing and conserving artifacts. It also serves as a research laboratory for archaeologists who use the information garnered from these artifacts to aid in the interpretation of the past.
Archaeologists visit the laboratory to see the objects being cleaned and identified and often lend a helping hand by cleaning or looking through books to identify what was uncovered. Tools such as magnifying glasses, microscopes and probes are employed to help in this stage of interpretation. Sometimes sophisticated equipment such as the electron microprobe are used to look at and evaluate the material in question. This equipment is more often used by earth scientists to examine the past environments of the earth, but it can easily be adopted for use by the archaeologist/conservator.