The right implements for your appliance
It is critical that you only use microwave-safe dishes and equipment when cooking with a microwave oven. Certain materials like metal and wood can cause fires to break out within your microwave and potentially cause serious damage to yourself and your home. Items that are microwave-safe will usually have a stamp marked “safe for use in microwaves,” or it may tell you on the box or user instruction manual.
If you have no idea whether an item is microwave-safe, there is a test that you can conduct to find out. First, place a microwave-safe cup of water and the dish in question (empty) into the microwave for one minute. The water should be hot at this point. Now touch the empty dish - if it is cool, then it is safe to use in a microwave. Microwaves act on moisture to heat food; they do not warm up the dishes you use. Dishes become hot only because heat is transferred from the hot food to the dish. An empty dish will stay cool if it is microwave-safe.
Dishes and your microwave - the breakdown
Glassware is extremely resistant to heat, so it is totally safe to use in the microwave. A word of caution: avoid using fragile glassware like stemware and bar glasses because these may crack when heated.
Check your plates for the microwave-safe label; most commercial dishes are microwave-safe. When in doubt, use the test outlined above.
If left to cook too long in the microwave, plastic can melt, so use it for short cooking times only.
Use paper plates in moderation - be aware that some may contain chemicals that may cause a fire in the microwave. They can be used for short periods of time when reheating food, but shouldn't be used to cook food.
Never use metal in the microwave. It can cause sparks that may result in a fire. This includes metal foil, dishes, utensils and any dinnerware that is edged in metal like gold, silver or platinum.
Note : Round dishes will cook food more evenly and efficiently than square containers or dishes.