Hi, as I start my journey of 're-discovery' of traditional printing techniques (salt printing, cyanotype etc) I would like to ask a couple of questions on chemical storage.

1) What is the best way of storing chemicals in powder form? They arrived in plastic bags, so I have stored the bags in a plastic selaed container/box and put them in my fridge - is this OK?

2) Do chemicals have a shelf life? I have some powder form of toners and D76 that have been on my shelf in the darkroom for 18months. Now I have a fridge in the darkroom will they be usable if I store them in the fridge for future use, or should I just bin them?

many thanks in advance,