I've burnt a few things in my microwave before and it takes a while for the smell to disperse. I suspect that the smell gets in to the air vent where steam is blown out (I have no idea what the technical name is). I'd just give it time, preferably leaving the door open to air it out. You could also leave something that absorbs odours in there while not using it, like a pot of baking soda.

Vinegar! It is a miracle solution to this problem. Put vinegar in a cup (I dilute with water, but you can use full strenght if the smell is THAT bad). Nuke it to boiling, let it sit in there a minute, then wipe down the MW. The vinegar smell will go away, leaving no smell. I've done this several times for the nefarious burnt popcorn and it works! Sometimes I have to repeat.

I second the vinegar.

I second the vinegar solution.

I use white vinegar. I buy it a gallon at a time because I use it for lots of other cleaning jobs.

After I used the vinegar and wiped down the microwave, I put a bowl of plain water in the microwave and nuked it to boiling.

It works very well!

Thanks everyone. I'll try that tonight!

I cooked "popcorn" on "baked potato" which nearly put the popcorn on fire. The burned smell went away eventually (think I tried vinegar and/or baking soda). The thing that has never gone away is the yellow discoloration on the inside of the microwave. It still works ok though.

Chop up a lemon into small wedges and put into a bowl add water to barely cover and nuke till boiling (2-3 mins) leave it in there for an hour or so and then wipe out. Much better smelling than Vinegar. Then take the used lemon and run through your garbage disposal to give it a fresh scent!

Blackened a micro-burger creating billows of thick white smoke. Scrubbed interior alternately with vinegar, baking soda, lemon. Smell still unbearable - vents and interior stained yellow. FINALLY followed someone's suggestion to use pure ACETONE nail polish remover for yellow stains - worked like a charm and did NOT damage the metal enamel interior. I also boiled a solution of lemon and water, and another of vinegar, baking soda and water which didn't help much with the smell. THIS WORKED BEST: In a quart size glass bowl I added 1/4 cup cheap PURE VANILLA (Costco) and a few drops PEPPERMINT OIL mixed with about 1 cup filtered water. Bring to a boil in microwave, uncovered and leave inside to steam for an hour or more then wipe interior dry. I have repeated this dozens of times and smoke odor is almost totally gone, replaced by a faint pleasant vanilla mint smell.

This post was edited by spinningfast on Tue, May 14, 13 at 12:34

After my son put a TV dinner in for 31 min instead of 3 1/2, the smoke and yellow stains were bad. The microwave got pulled out of its built in shelf and the shelf was very yellow and smelly. I used candles and open windows for hours, then many of the suggestions above to decrease the smell (coffee, vinegar, lemon juice), but boiled them on the stovetop and left them on a low boil for up to 1/2 hour. i tried the acetone on the shelf and it took some of the yellow off but Fantastik did the rest. The yellow ran down the walls as i sprayed it on! It took the stains and much of the smell away. Now onto the microwave that is outside, airing out...

Put a pyrex 2 cup measure half full of water in the micro and set for 4 minutes on high.....open the door, allow the water to cool, dump and repeat.
Vinegar and soda or whatever works when you can wipe the surfaces, but for odors hidden in the fan....a little steam....and repeat.....and repeat.

@careercounselor I tried the vinegar and it didn't really work. Tried the coffee grounds mixed with want and worked!! Thanks for the tip.

Haha, just tried the coffee trick... which I think has worked... BUT... the coffee boiled over (new microwave so I clearly don't know it's limits yet)... and now I've got another mess to clean up!! LOL!! One of those days!

To get the yellow stain out, use Dawn Power Dissolver spray (for baked-on or burnt-on pots, pans and dishes). Let sit up to 30 minutes per instructions, wipe out and rinse. Works like a charm.

BTW, shezwa86, I did the same thing yesterday. After cleaning up the burnt mess and the yellow, I had to clean up the boiled-over coffee. Then I put the 2 Tbsp of coffee and 1/2- 1 cup of water into a quart glass measuring cup to give it plenty of room to boil for a couple of minutes and not spill over. I let it sit for 5 minutes and did it again. Then I left it in the microwave for a while to allow the steam to go through the vent. It worked somewhat, but I still will give the vinegar a try (or lemon juice or vanilla or cinnamon).

Thank you, thank you all who recommended coffee --IT WORKED. Burnt a slice of quiche to a black crisp and tried everything else to get smell out. I am so glad their are sites like this for help.