How do I clean the inside of my microwave oven?

Unplug the appliance before cleaning, then wipe the cavity with a slightly damp cloth after each use. For easier cleaning of cavity walls, place half a lemon in a bowl with 300ml of water and heat on 100% microwave power for 10 minutes, then wipe clean with a soft, dry cloth. Never use harsh abrasive cleaners or sharp metal scrapers, especially on the door glass, as they can scratch the surface and may cause the glass to shatter. (Page 8)