19 Things You Should Never Microwave BySamantha Bansil, 08/18/2021 Gourmandize shares Share on Facebook Share on Twitter Pin it Share on WhatsApp Share on Google+ 5/19 Previous Next © Getty Images Leafy greens Leafy greens like spinach, kale and others can potentially spark when heated in the microwave, according to NPR. Why that happen isn't so simple to explain, but basically it has to do with physics and electric properties.