Solvents and their mixtures used in restoration and cleaning of wood were formerly introduced on the basis of practical experience. Cleaning is presented as a physico-chemical process, with the aim of the detachment of non-wanted materials bound to the surface of the object by H-bonds and van der Waals forces. Solvent theory can help in finding the optimum way of cleaning. Teas solubility diagrams can be used to select solvents for cleaning without damage. A study of the Teas diagram was carried out with solvents for the dissolution of proteins and polysaccharides. -- AATA