I was at a photographer's studio yesterday because he had run an ad in the paper to sell some MF gear with a move to digital. They also had sitting on the shelf 2 16oz plastic containers of Kodak Metol (direct from Kodak) and I can't find an expiration date. The gentleman told me another photographer who worked for him bought it abut 3 years ago. He said I could have it for free. I was wondering if there is a time at which metol would lose its potency? Neither container has been opened, both still have seals intact. I know I could mix up a batch of home brew dektol and try it, but i hate to waste any other chemicals if the metol would be "expired". Any way to test it?