Was metal or aluminum foil used in the microwave?
Aluminum foil and some metal can be used in the microwave oven. If not used properly, arcing can occur and cause damage to the microwave oven.
Acceptable for use:
Racks and bakeware supplied with the microwave oven (on some models), aluminum foil for shielding, and approved meat thermometers may be used with the following guidelines:
Do not allow aluminum foil or metal to touch the inside cavity walls, ceiling or floor.
Always use the turntable.
Do not allow contact with another metal object during cooking.
If not used properly, arcing can occur and cause damage to the microwave.
Do not use:
Metal cookware and bakeware, gold, silver, pewter, nonapproved meat thermometers, skewers, twist ties, foil liners such as sandwich wrappers, staples and objects with gold or silver trim or a metallic glaze should not be used in the microwave oven.