This recently came up at work and I thought I would pass it along. Generally, any large metal container would work, but a bag would be nice for those small electronic items..... Introducing the faraday bag: https://www.amazon.com/s/ref=bl_dp_...P+BAG+FROM+BLACKOUT+BAGS&tag=survivalmonke-20 Do they work? I can verify that they positively block RF waves. Never took one to an EMP test, but in theory....?