Proper care and maintenance for both the toaster oven and microwave include keeping the oven cavity clean and free of grease build-up. In the microwave oven, this is extremely important around the door because the seal must stay in tact. Microwaves in proper functioning will not operate if the door does not shut completely; if it does, it needs to be serviced immediately to avoid further exposure.
With some microwaves, closed glass jars, whole eggs (even pierced), and bottles with narrow necks should not be used because they may explode during cooking.
There are also air vents located on the top or sides of microwave ovens. Make sure these vents are kept open and free of food particles and debris. These vents are necessary to keep the oven’s mechanical parts from overheating.
To reduce the risk of fire in the oven cavity, don’t overcook food. If cooking food does ignite, keep oven door closed, turn off oven (or cancel timing device), and disconnect power cord or shut off the power from fuse box. In the unlikely event these precautions must be exercised, have the oven serviced to evaluate the possibility of further usage.