Polyvinylamine Gel as a Cleaning Agent for Removing Mineral Crusts from Archaeologically Important Stone Artifacts

When stone objects are excavated at archeological sites, they are often covered with crusts of mineral deposits on the surface, which seriously obscure their aesthetic value, especially in the case of polychrome stone statues. To remove these carbonate crusts without damaging the underlying painting and stone matrix, a gel-based cleaning system combining polyvinylamine (PVAm) and acetic acid is proposed. The structures of the PVAm cleaning gels were characterized using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Employing samples of the typical types of stone used in polychrome statues (marble and limestone) and painted samples, the cleaning efficiencies, surface morphologies, and chromatic alterations resulting from treatment with the different cleaning gels were evaluated and compared. Based on the obtained results, the optimal composition of the PVAm cleaning gel was determined.