Operators, your field exercise is over and you’ve got 5-gal cans of leftover fuel. The rule is: put that fuel into any vehicle or system that uses and needs it, but don’t store it.
If you store the cans outside, rain gets in. Store them inside or outside, and heat and cold cause condensation – more water – inside the can.
Either way, the fuel is contaminated, and contaminated fuel can ruin an injector pump.
Warning: Storing fuel is also dangerous. A spark could blow up the storage can, the storage shed and anyone nearby.