Overheating a plastic food container in the microwave could result in melted plastic. The lids on some plastic takeout containers may even start melting before the food beneath them gets hot. The end result: a stinky microwave and a potentially ruined meal. To get a burnt plastic smell out of a microwave, air it out, then clean it with odor-busting natural cleaners, such as vinegar.
Steam Cleaning the Microwave
Cleaning the inside of the microwave with steam serves two purposes: it helps remove that plastic odor, as well as any potential grime left behind by food splatter. Vinegar is the secret ingredient that gets rid of odors and cuts through caked-on foods.
To steam-clean the microwave, fill a glass microwave-safe measuring cup half way with tap water. Add 2 tablespoons of white vinegar, then place the cup in the microwave. Heat the liquid for two to three minutes, or just until the inside of the microwave window steams up. Leave the microwave door closed for at least 10 minutes, then open it.
Use a sponge and the liquid in the measuring cup to wipe down the entire interior of the microwave. Leave the microwave door open to allow the unit to air dry.
When the Microwave Vent Smells
If you've already cleaned the microwave and new odors arise when you use it, it could be that your microwave vent smells. Note whether it smells the same as the melted plastic odor you noticed before you cleaned the microwave. It's possible some of the air circulating through the heat vent in the microwave still smells of burnt plastic. If it smells more like an electrical issue, or if the microwave isn't working properly, the appliance may need to be repaired or replaced.
If you're sure the odor is just a lingering melted-plastic smell, the odor will go away on its own. You can also try the steam-cleaning method again, adding a few squirts of lemon juice.
Burnt Odors in New Microwave
A brand new microwave may also smell like burnt plastic or an electrical malfunction the first few times the appliance is used. In some cases, you may even see smoke. This is normal as the circuitboard inside the device heats up for the first few times.
A combination microwave/convection oven may also produce unusual plastic or burning odors from time to time, especially when the appliance is new. This could be the convection heat element warming up; it should stop after using it a few more times.
Is the Burnt Plastic Odor in House Dangerous?
A microwave burnt plastic smell in the house isn't dangerous if the microwave has been used properly. Microwaving plastic items to purposely melt them, however, may emit harmful fumes. To get rid of the burning plastic smell in the house, open the windows and turn on ceiling fans. If you have box fans, place those in or near windows, with one drawing in fresh air and another on the opposite side of the house blowing out the stench. Boil a pot of water with a few sliced oranges or cinnamon sticks in it to emit a pleasant aroma.
Kathy Adams is an award-winning writer. She is an avid DIYer that is equally at home repurposing random objects into new, useful creations as she is at supporting community gardening efforts and writing about healthy alternatives to household chemicals. She's written numerous DIY articles for paint and decor companies, as well as for Black + Decker, Hunker, SFGate, Landlordology and others.