DCM, Thats what I thought it was but unsure. It's only 6 months old and have kept in frig so I think it's still ok but I did wonder that also. Moved recently and it rubbed on something to where it couldn't be read. I also did a search and found a site that said to mix it at 10:1 and it seemed a little weak than I remember. Also, people that make custom fly rods use ammonium something with distilled h2o and add that to the 2:1. Allows more working time?
Thanks
Tracy