Examples of the water soluble organic solvent useful for this purpose include: alkyl alcohols each having 1-4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, m-butyl alcohol, sec-butyl alcohol, tertbutyl alcohol and isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones and keto alcohols such as acetone and discetone alcohol; ethe