Hello, Can anyone describe a way to determine if a gallon of C-41 bleach that has been sitting for some time (probably over a year and a half) is still any good? I believe I had used about half the capacity of 120 rolls 135 format before I capped it and stowed it last. I know Kodak lists the shelf life as "indefinite", but I still would like to know if there is some sort of leader test or other sort of test that I can do. I also have a bottle that is well over two and a half years old, but I know this one is near the end of its capacity, having gone through two sets of the other chemicals using the same bottle of bleach. Thanks in advance.