Some chemicals become unstable with age. We were warned about a chemical used in fish culture, picric acid, that crystalizes with age, with the crystals becoming explosive. We have had someone from the chemistry department at the local university look at materials in the collection and make recommendations as to their safety, what should be dumped, what was okay. Chemicals on exhibit need to be secure from visitors. Randi DC Booth ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ museum-l.html. You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] The body of the message should read "Signoff Museum-L" (without the quotes).