Sustainable solutions for removing aged wax-based coatings from Cultural Heritage: exploiting Deep Eutectic Solvents (DESs)

This work investigates the potential use of hydrophobic Deep Eutectic Solvents (DESs) in cleaning treatments on works of art covered by aged nonpolar substances. The interaction between the selected DESs and three waxes (beeswax and two microcrystalline waxes – namely, R21 and Reinassance) was evaluated through solubility tests and cleaning tests performed through a common approach used by restorers. The effective removal of the wax layer from the mockups was assessed by loading the waxes with a fluorescent marker (Rhodamine 6G) and observing the treated specimens under visible and ultraviolet light using multispectral imaging. The presence of solvents’ residues on the treated surface was examined through Fourier Transform Infrared (FT-IR) spectroscopy in the Attenuated Total Reflectance (ATR) mode. FT-IR ATR was performed to assess the presence of wax on the swabs used for the cleaning tests, confirming the actual removal of wax from the mockups.