I use glass or the original plastic with a blast of Bloxygen (Argon gas) before sealing. I've kept DD-X, Sprint Film Developer, Perceptol and even Studionol (R09 Spezial) after opening with no problems of spoilage. Months of use from a bottle of R09 Spezial. The first can of Bloxygen paid for itself several times over by allowing a single bottle of DD-X to last and last.