Burnt popcorn -- I don't think there's another odor that will linger on in the kitchen longer. I mean, why can't the delicious fragrance of freshly baked cookies hang around for days?
Unfortunately, the odor I'm dealing with today is even worse... burnt plastic and charred chocolate chip waffle, courtesy of one hungry seven-year-old boy setting the timer for five minutes instead of 15 seconds. I cleaned the microwave thoroughly, but that horrible, overpowering scent endured.
In a moment of desperation it occurred to me that coffee grounds work well at absorbing odors. So I mixed up approximately two tablespoons of ground coffee with one-half cup of water and popped it in the microwave for about three minutes. Voila -- no more burnt smell!
If it can tackle burnt plastic, burnt popcorn should be no match...