No need to be afraid of lipos. You must give them proper respect. If you don't respect them, they will bite you hard. Possibly burning down your house
+1 on the metal storage/charging box.
If you are using an ammo box be sure to remove the rubber gasket. You want to let it vent.
I added drywall dividers to my ammo box. I have enough room inside the box to have a plastic bag of sand to cover the batteries. If one goes, hopefully the bag will melt, releasing the sand to contain the fire. Without the dividers, if one battery goes they all go.
Here is a video that explains.