When I started using TF4, some months ago, I kept my regular fix (Zone6 film and paper fix, mixed from powder) and stop (I mix 28% from a gallon of glacial purchased from Kodak years ago) until I knew I wasn't going back to the acid stuff. I'm not using these any more, and will donate what's left to a local teaching darkroom, but would like to use the gallon jugs to mix up a whole gallon concentrate of TF4 at once, since it's difficult to keep suspended while measuring. These are good jugs, either glass (the old amber ones), or Kodak translucent jugs, the kind you got when purchasing either Rapid Fix, or other darkroom chemicals by the gallon in the 80s and 90s. Can I soak water in them for a week or so, or maybe a weak solution of Sodium Sulfite to rid them of any acid traces and use for TF4? I assume a thorough water rinse is enough for the glass.