5 CONCLUSIONS

Work on the mechanisms and effects of cleaning systems for oil paintings continues. Hansen's solvent parameters provide one way to evaluate trends that appear in the effects of solvents. The Teas plot, which compresses the three variables of solvent properties into a two-dimensional plot, is suitable for general use but may result in some anomalies. The effects of solvents must be considered whenever they are applied to a paint film, even when they are not specifically being used for cleaning. Solvents used to apply varnishes also act on paintings, and the varnish-solvent mixture can act as a poultice in leaching soluble materials from a paint film to which it is applied. There is less information on the process and effects of the use of gelled and soap solutions. It is clear, however, that these materials behave in some ways much like solvents. More study of the use of these materials is required, especially on their mode of action and the possible continuing effects of the residues of the involatile materials that they contain.