Both microwave and toaster ovens can be used for warming and cooking most foods. The factors determining which one is most appropriate are preparation efficiency, the quality of taste, the texture, and the quality of appearance. Depending on the size of the toaster oven, many small items can be baked, broiled, or toasted with utensils such as metal or glass baking pans, broiler pans, casserole dishes, roasting pans and drip trays. Microwave can be operated with these same utensils as long as the material composition is heat proof plastic or glass. Most microwaves cannot function properly when metal containers and utensils are used; arcing (lightning like flashes) may occur. Metals can be identified by their shiny appearance, or by names like aluminum, stainless steel, cast iron, or copper etched on the utensil, not all plastics and glassware can be used in the microwave. Some plastics will melt or breakdown, and glass may crack or break under the heat of hot food substances.
In order to determine if a glass item is safe for microwaving, read the label on the container; it should specify “microwave safe” or “heat resistant.” A simple test will determine if a given or purchased glassware or plastic is suitable for microwave use. Fill a glass or ceramic measuring cup with water, and place it in the center of the microwave oven. Place the container to be tested next to the cup. Microwave on high power for 2 1/2 minutes. The container is microwave safe if it is cool to touch and easily handled. If the container is warm or hot, it means that the container has absorbed the microwave energy. In this case, it should not be used because the utensil may melt, crack or break.
Ceramics should be avoided because some may contain small traces of metal which can cause damage to the magnetic tube over an extended period of time. Ceramics are those utensils which are made of clay or pottery. Brand names may include Earthenware or Farberware.