1 cup water
1 quart warm water
1/4 cup baking soda

To loosen dried-on food, put 1 cup water in a microwavable cup and heat in the microwave until it boils; turn off the microwave and let the water sit for 1 minute. Dissolve baking soda in 1 quart warm water and, using a sponge or cloth, wash the interior of the microwave with this solution to clean and deodorize it.