Be very careful with anything metallic put into a microwave. Even a small amount of metal can cause an arc with bad results and it's very scary.
I've learned the hard way over the years to be very, very careful with microwave ovens--the one I have now runs very hot compared to others I've had.
(Speaking of microwave ovens, just an aside- once last year my husband put a half-loaf of frozen bread which was wrapped tightly in plastic wrap into our microwave and started it and within 20 seconds the bread and wrap were actually on fire. We were lucky the house didn't burn down). Now I don't allow him in the kitchen by himself--just kidding. Sometimes I do.
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