I dno,
I think your spozed to keep it airtight, and in the freezer at all times (apart from when your preparing batches of it) which, is why i think people make a months worth or more at a time, as it saves you having to keep exposing the stuff to air.
Ive got my batches pre-made in air tight vacumme sealed food bags, keep it all in the freezer, and wrap each `hit` in tin-foil to keep air and condensation etc.. out.
I think the thing with RU is it's probobly easier to `ruin` then most people think it is, hence why there are so many stories where people reported it did nothing for them, and some that said it grew alot of hair back.....