Unplug the microwave
Remove the turntable and wash it with warm, soapy water
Wipe the interior with a mixture of equal parts water and white vinegar
Heat a bowl of water with lemon slices for 3 to 5 minutes
Let the steam sit inside the microwave for 5 minutes
Wipe down the interior with a clean cloth
Clean the door, seals, and vents
Sprinkle baking soda inside and leave it overnight
Remove the baking soda and wipe the microwave clean
Leave the door open for a while to air it out