Abstract: The invention provides a method of preparing a supersaturated solution of an inorganic solute in an aqueous solvent, to such solutions and to a method of treating wood by impregnating it with such solutions. The method of preparing the solution involves mixing an aqueous solvent and salt solute together with an organic dopant comprising an emulsifier and an oil or wax, so that the eventual solution comprises an aqueous phase in which the solute is dissolved, the proportions of the constituents being selected so that the aqueous phase is a supersaturated solution of the inorganic salt solute in the solvent.