Is there a way to test and see if XTOL is still good? I mixed some up around the beginning or mid part of July, when I got my F100 and was testing it out. I have not developed a roll since then. The XTOL was newly mixed, and has sat in a black jug in a cabinet in the utility room ever since then. I have two rolls that I need to develop, but I don't want to risk the XTOL being bad.