The microwave habits that do the most damage are running it empty, putting metal inside, leaving food splatter on the walls and using it after the door has been bent or damaged. Microwave-safe containers, a clean cavity and a door that closes firmly are the three things to keep in check.
Mistakes at a glance
| Habit | What it leads to | Do this instead |
|---|---|---|
| Running it empty to "test" it or by accident | Sparking, and possible damage on some models | Always have food or a cup of water inside; check your manual |
| Using metal pans, utensils or foil | Arcing and possible damage to the oven | Use cookware labeled microwave safe |
| Leaving twist ties on bags | Arcing, because the wire acts like an antenna | Remove twist ties before heating |
| Letting food splatter build up on the walls | Spatter that overcooks and sparks | Wipe the cavity, its edge and the door with water and mild detergent |
| Heating water longer than the manual suggests | Superheated water that can erupt when moved | Follow the manual's heating times for liquids |
| Using it with a bent, warped or damaged door | A door that may not seal properly | Stop using it and have it checked |
| Heating in containers not made for microwaves | Melting, cracking or warping | Use cookware made for microwave use |
The ones that matter most
Running it empty
A microwave needs something in it to absorb the energy. The FDA notes that some ovens should not be operated when empty and refers owners to their instruction manuals. LG lists running the microwave while empty as one cause of sparking. It can happen by accident, for example when the timer is started before the food goes in.
Metal, foil and twist ties
The FDA says metal pans and aluminum foil generally shouldn't be used in a microwave oven. GE Appliances explains that metal twist ties act as an antenna and will cause arcing and possible damage to the oven, and that loose pieces of foil sticking up from food work the same way. GE also says small amounts of foil can be used safely only when its guidelines are followed, and that metal and foil can be used in the convection mode of a microwave convection oven, so the manual for your model decides. LG lists metal utensils and twist ties among the causes of arcing. Plates with metallic trim count as metal too.
Letting splatter build up
Food left on the walls keeps absorbing energy every time the microwave runs. LG says food crumbs and spillovers can overcook and cause sparking, and that damage to the cavity's interior can also cause arcing. The FDA recommends regularly cleaning the oven cavity, the outer edge of the cavity and the door with water and a mild detergent. Covering food while it heats keeps most splatter off the walls.
Using a damaged door
The door keeps microwave energy inside. The FDA says not to operate a microwave oven if the door doesn't close firmly or is bent, warped or otherwise damaged. Slamming the door, hanging items from the handle or using an over-the-range door as a shelf all put stress on its hinges and latches.
Never open a microwave's outer case. Microwaves hold high voltage inside even when unplugged, so internal repairs belong to a technician.
Signs it's already caused a problem
- Sparks, flashes or popping inside, even with microwave-safe dishes
- A burned spot, bubbled paint or a scorched cover panel on an inside wall
- A door that doesn't latch firmly, sits crooked or has a damaged seal
- Food heating much more slowly than it used to
- A burning smell while it runs
If any of these show up, stop using the microwave and book a microwave repair visit. How it's plugged in matters too; see extension cord mistakes with major appliances.
Sources
- FDA: Microwave Ovens
- LG: Why Is My Microwave Arcing or Sparking?
- GE Appliances: Microwave, Using Metal or Foil
Habit to keep: Something inside every time it runs, and nothing metal unless the manual allows it.
If your microwave has sparked or the door won't close firmly, call ProFix San Antonio at (210) 761-6006.