I recently bought out a darkroom at an estate sale and there are quite a few boxes of Microphen and ID-11. These appear to be pretty old but are still sealed. Can anyone tell me if the raw mixes have any kind of shelf life? I hate to waste this developer if it is still good, conversly I would hate to ruin that one sheet of film with the Pulitzer winning picture on it(posted 8930 days ago). Thanks, -harry