Unplug the microwave, and take out the tray.
Discard the melted plastic container if you haven’t already.
Wash the tray with warm, soapy water, and rinse it well. If plastic has melted onto it, allow it to soak in warm soapy water for 10 to 15 minutes before scraping it away with a blunt utensil, such as a wooden or plastic spoon or spatula.
Wash out the inside of the microwave with warm, soapy water. Use a clean cloth or sponge that is wrung out well to avoid getting too much moisture in the microwave.
Wipe down the inside of the microwave with a clean, damp cloth. Once the soapy residue is gone, use a dry towel to wipe up as much moisture as possible.
Leave the door to the microwave open so it can air out for 15 to 20 minutes.
Plug the microwave back in, and replace the tray once it is clean and dry.
Add 2 to 3 tablespoons of fresh ground coffee to a microwave-safe cup or bowl with 1 cup of water.
Heat the coffee and water for two to three minutes in the microwave. Heat another cup of grounds and water if needed to completely eliminate the odor.