Feasibility of different cleaning methods for silver-copper alloys by X-ray fluorescence: Application to ancient Greek silver coins

• Ancient Greek silver coins were selected to be cleaned by different procedures.
• Five cleaning procedures were used.
• Different elements were measured before and after each cleaning procedure by XRF.
• Rochelle salts procedure was found to be the most suitable for a systematic work.

Archeological pieces with high Ag concentrations often have a surface enrichment of Ag. Usually, researchers in this field do not agree on the causes of these enrichments, one of which could be the cleaning procedures. In this work, a set of 18 ancient Greek silver coins was selected to study the effects of different cleaning procedures in terms of producing a surface Ag enrichment. The aim of this study is to find and select the less aggressive one in terms of the lower modification of Ag concentrations and visual aspect. These coins were analyzed by X-ray fluorescence (XRF) before and after each cleaning procedure.