Is it possible?
I use to have all my creo in its original zip-lock bag but transferred it to a milo tin for convenience when taking it with me to gym. I haven't supplemented it for over 4 months (it would be about 10months old in total) and it was 'clumped' together when i re-opened it.
I had to shake the tin to break it back into powder if you get what i mean.
This dodgy or would it still be useful?