things like 5 gallon bucket full of sand with lid are common place at ama fields...... it's how you want to transport a lipo that got hot.
to charge you should use a lipo charging bag and most people utilize concrete, brick or some other un burnable material to set them on.
That ammo can will get hotter than hell if it ever burns, keep it on something that can't light. Fireplace is a good spot, garage away from walls, etc. i use my stove top to charge on,,