For handling stock solution: Thaw for 5-15 minutes at room temperature. Do not thaw by heating. The unused portion should be returned to the freezer as quickly as possible. We recommend aliquotting stock solutions into several tubes to prevent extended room temperature exposure over many uses. For handling working solutions: Dilutions of the stock solution should be made as needed, using water or aqueous buffer (pH 7-9) as the diluents, and then stored on ice. Working solutions should be used immediately.