Tried out this simple technique over the weekend to clean up the inside of the microwave which had gotten pretty nasty from spaghetti sauce splatters, etc. Simply take a lemon, cut it in half, place in a microwave safe large bowl or Pyrex measuring cup, add about 2-3 cups of water, then microwave on full power for about 5-10 minutes. The boiling lemon water creates a nice, lemon-scented, slightly acidic steam bath inside the microwave which loosens all the splatters and grime. Carefully remove the bowl (it's hot of course), then wipe down the inside with a clean paper towel or two. Works like a charm.