Line the inside of the or with styrofoam or foam core board or newspaper stack
Place electronics inside.
Close and seal with aluminum tape.
Attach a copper ground wire to both the box and a copper stake.
You may acquire your metal box by consolidating your ammo or by moving your older files to a plastic water tight file box. Or, if you are lucky like I am, you can use what you have or ask your mom if you can have that dusty old box and put it to good use.
I am interested in preserving digital photos and photo reading devices, digital books and an e reader, and the solar charger and batteries to operate them. I have a library of books I am assembling and this will be a good place to store them and protect them.