Article: Fill a bowl with equal parts water and white vinegar. Put the bowl in the microwave for three minutes on high. Leave the microwave door shut for a few minutes after the steam, then take out the bowl. Rub the interior of the microwave with a clean towel or cloth. Vinegar is a powerful cleaning agent, and the steam should have eliminated the smell of the burnt popcorn. Vinegar will leave a vinegary scent behind that will dissipate after a couple days. If the steam-treatment doesn't work, you may want to be more direct with the vinegar treatment. Pour about half a tablespoon of vinegar and a teaspoon of baking soda on a damp sponge. Heat the sponge in the microwave for 20-30 seconds, and then scrub the inside of the microwave with the sponge. A scrub brush is a more aggressive tool than a sponge, and its bristles may be able to get into the nooks and crannies that a sponge can't. Dip the scrub brush into the water-vinegar mixture, then scrub the inside of the microwave.

What is a summary?
Do a steam-clean process with vinegar. Pour vinegar and baking soda on a sponge and clean the microwave. Use a scrub brush.