Here's how to keep your microwave spanking clean:
: Heat a bowl of water with a tablespoon of white vinegar in the microwave. Then wipe down.
Microwave a bowl of water with a few drops of dishwasher in it, until it starts to steam. Then wipe the inside of the microwave.
Take out the glass tray or turntable and wash it like a dish.
Microwave two halves of a lemon till the insides are steamy. Then wipe down.