I have no idea if this will work. This is from the internet on how to get the popcorn smell out of a microwave oven, which you may know if pretty stubborn. You could heat the mixture in your microwave and then transfer it to your freezer and leave for awhile. I would try it several times.
Fill a bowl with 1/2 cup water and 1 tablespoon white vinegar.
Microwave it for 4-5 minutes and leave it with the door shut for 10-15 minutes.
Steam will loosen smell-causing detritus stuck to the walls. ...
After the waiting period, remove the bowl and wipe the inside of the microwave down with a paper towel.