Bob, when I used to use Kodalith A & B developers I used to put them into the plastic bags from the home brew wine kits. The kind you put into a box with a plastic spout on the end. The have a UV or light exposure coating on the plastic and you can get most of the air out of them when you fill them. Once in the box you just open the spout and pour out what ever you want as the outside air pressure collapses the bag. It worked pretty good and kept the developer fresher longer.