Cleaning archaeological bones: Influence of water, ethanol, and acetone on microhardness

The application of conservation treatments on archaeological bone is, in many cases, a necessary step for its study. Cleaning interventions can generate modifications on the surface of the material or even modify elements of the study. The variables involved in this process have been scarcely characterized. The present study reports on the characterization of how different liquids commonly used in cleaning processes can contribute to the onset of modifications by influencing microhardness. Three media were experimented with water, ethanol, and acetone. The Knoop microhardness test was used to measure the hardness of bone samples from two archaeological sites: Gran Dolina and two localities at Barranc de la Boella, before and during exposure to the liquids. Results note that all the solvents produce a decrease in sample microhardness. These variations in hardness should be considered when cleaning because they make it simpler to damage the bone surface with cleaning tools.