Hi all...I think this is my first post! I was wondering if any of the following chemicals have a short shelf life...thanks a lot. Gu Pot. Ferrycyanide Amm. Di-Chromate Pot. Carbonate Pot. Di-Chromate Oxalic Acid Ammonium Citrate Silver Nitrate Sodium Thiosulfate Sodium Acetate Borax Rochelle Salts Tartaric Acid thanks a lot!