biodiesel storage containers

[bamba]

I just purchased both my first MB and batch of B20 about two weeks ago. I filled the tank and also bought about 50 more gallons, divided into 5 gallon containers.

I'm starting to worry about the containers filled with B20. Not because there is a problem or anything - they look fine, no leaks, etc. I dumpster-dove for some old 5-gallon containers that restaurants receive their virgin fry oil in (don't worry, I thoroughly cleaned and dried them). See the pic below of the containers in the back of the wagon.

Now I'm wondering - are these containers safe to store B20 (and eventually B100) in for long periods of time (1-2 months)? I assumed it'd be okay, but now I'm starting to worry... Does anyone have any experience or advice on this?