Examples of the water soluble organic solvents which can be used with water include alkyl alcohols having 1 to 4 carbon atoms, e.g. methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol; amides, e.g. dimethyl formamide and dimethyl acetamide; ketones and ketoalcohols, e.g. acetone and diacetone alcohol; ethers, e.g. tetrahydro