Fill a microwave safe bowl with white vinegar. Alternatively, pour 1 cup of water into the bowl and add 2 tbsp. of baking soda. Place the bowl in the microwave and close the door. You can also use 1 cup of water with ½ cup of lemon juice.
Set the microwave on high and allow to cook for five minutes. The steam from the bowl's contents will loosen any stuck on grime and naturally remove the popcorn odor.
Open the microwave door and remove the bowl. Saturate a cloth in the mixture and wipe the inside of the microwave clean.
Rinse the inside of the microwave with a clean cloth dampened in cool water. Wipe dry with a towel.
Repeat the process as needed.