Examples of organic solvents that can be used for the purpose of the invention include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide, ketones and keto-alcohols such as acetone, diacetone alcohol, ethers such as tet