Also store some electronics, spare ham radio, spare amfm radio, in a faraday cage. I built mine using old shoeboxes and strong aluminum foil and sealed with aluminum tape. I also keep my daily electronic gizmos in an non operational micro wave. My daughter calls me anal retentive. But They all know where to show up when the shtf. Taught the grandsons how to shoot rifles and hand guns.
The old microwave oven idea is great. Do they really work? No micro wave out, none in I suppose.