Is the inside of your microwave caked with bits of hardened food? You can give it a good cleaning without scratching the surface with harsh cleansers or using a lot of elbow grease. Just mix 3 tablespoons lemon juice into 1 1/2 cups water in a microwave-safe bowl. Microwave on High for 5-10 minutes, allowing the steam to condense on the inside walls and ceiling of the oven. Then just wipe away the softened food with a dishrag.