Unknown material
Transfer food when you cannot identify the container or its temperature rating.
Five reasons to stop and check
Metal in a microwave
Metal, foil and metallic decoration can arc and start a fire.
Sealed container
Pressure can build rapidly; vent only as the product instructions direct.
Cracked glass
Damage and thermal shock can lead to sudden breakage.
Blocked airflow
Air fryers need circulation. Loose liners can lift into the heating element.