I have recently purchased enough AGFA chemistry to last me at least 10 years at my current rate of consumption. They all came in plastic bottles (HDPE). Other postings have mentioned the idea of transferring the liquids to amber glass bottles and then sealing out the air with a squirt of protectan. I really only want to do this if someone can give me a good reason to. For example, does plastic allow oxygen to pass? As it is I will already have them in a small refrigerator (cold and no light). FWIW, the products I purchased are Rodinal (yeah I know it lasts forever - but in a plastic bottle - they used to come in glass), Neutol Plus and Sistan. So is there *any disadvantage *to keeping my liquid chemical concentrates in their original plastic containers? regards Peter