We recently dissolved our X-gal powder in DMSO instead of DMF, as it was before, because it is less toxic, and sparing all the troubles of getting it from the locker in the basement
It was stored in -20.
But colleague was not as happy with the fact that DMSO freezes at -20, also people usually store it in aliquots to prevent repeated freeze/thaw cycles. That is not usable for the way this lab works, since they want everything just "easy to use and simple".
I couldn't find anywhere, if you can store it in 4 C or some other way to keep it unfrozen (in dark of course). Or how much the repeated refreezing will hurt it (and that is needed to be aliquoted anyway).