Clean your microwave easily. Clean a crusty microwave with a soaked sponge (and sanitize a sponge this same way). Soak a sponge in water and cook in microwave for one minute. Careful, it will be too hot to handle with bare hands. The moisture will loosen grime on your microwave and make it easier to clean. To sanitize a yucky sponge, soak it in water and vinegar and microwave for one minute.