Lemon Microwave Cleaner - Add 4 tablespoons of lemon juice to 1 cup water in a microwave-safe, 4-cup bowl. Boil 5 minutes in the microwave, allowing the steam to condense on the inside walls of the oven. Then wipe clean.
To determine whether or not a dish is safe to use in the microwave, pour 1 cup water in to a glass measuring cup. Place the measuring cup in the microwave in the dish being tested. Microwave at HIGH for 1 minute. If the dish being tested is warm and the water cool, the dish is unsafe.