Thermoplastics are ideal for microwave cooking as they can tolerate very high temperatures. Some plastics may warp and discolour dur to the heat of some foods, ie. those with a high sugar or fat content. Melamine or Urea plastic are unsuitable for microwave cookery since they absorb heat. Paper Do not use paper or paper products unless they are specifically designed for microwave usage. 9 Metal Metal containers should not be used. Microwaves cannot penetrate through metal and therefore the food