Just use a small microwave they come in different strengths!
I haven’t thrown away any microwaves.
I too have an old dud microwave and use it for storing my SONY ICF-SW7600GR (FM/SW/AM) plus batteries, hand crank emergency radio, etc. MW was an old GE unit I bought in 1976...died last year!! Now there's good service out of an appliance!
Doesnt work. Dont believe me....put a portable FM radio in it tuned to your favorite station. Then try AM.