I obtained some XTOL a while back (to make 5 liters, I believe), and thought I would be keen and measure out 1/5th of each of the two powder packets, and make just a liter of solution. My thought was, I could store the remaining chemical in two plastic air tight plastic containers. Well, it has been maybe 6 months, and the chemical in one container has become like a "cake", and maybe even a bit brown tinged in color. I'm sure it's no good. Sigh. My question, is there a way to store these two components, once the original foil packets are opened? I am a low volume user, and making all the stock solution, and then letting it sit on the shelf, in bottles, would result in waste as well, at the rate I use it. Any ideas?