In order to be used in a microwave oven,the containers must be of a material,which allows microwave to pass through it to the food. The materials fit for are as follows:
China and pottery, ovenproof glass and glass ceramic dishes are perfectly suitable for microwave cooking.
However, fine bone china and ordinary glass should be used for short periods only,as they would crack with excessive heat.
Paper cups, cartons, cling films and thermo plastics are suitable for microwave cooking.
Metal or foil containers should never be used as these reflect the microwaves.
Melamine ware also tends to crack when heated.