Coffee Grounds to Remove Odors in the Microwave

I cooked some corn dogs that were old and frost bitten. Boy, did I burn 'em. Anyway, I had a hard time getting the smell out of the microwave. Tried everyone's tricks and tips. They reduced the odor, but it was still present, especially when I'd microwave something else.

So I left a small plate with coffee grounds in the microwave overnight, and was very happy to discover that the smell was totally gone. This morning, I stirred the grounds up and put it back in the microwave (not taking any chances).