Originally Posted by Tom Hoskinson from the thread link I posted earlier: Benzotriazole can also decompose slowly in alkaline solution. A neutral organic solvent is best for long shelf life. Ethyl, Propyl, or Methyl alcohol are best. Ron Mowrey Hmmm...all the alcohols I know are quite WET. I think dry BZT lasts a very long time. I've had no trouble using stuff that is years old. Wayne