How old do the microwaves have to be?
I would like to put my crank radio into one.
“I would like to put my crank radio into one.”
the microwave can act as a Faraday cage, but a double wrap of aluminum foil is just as effective. ANY closed conductive box can be a good Faraday cage.
You know the wire mesh that is visible inside the glass on the door? That is the Farady aspect. That wire mesh encompasses the entire device and is what makes them a tool against EMP.
I used the word "old" simply because folks rarely offer new ones on Craigslist. It does not need to be a working device, as the thing that makes it valuable to us is the wire mesh.
On the other hand, you can buy the mesh separately. It is expensive, though.