Recipient Test
If in doubt about the use of glass, glazed ceramic or porcelain dishes in the microwave oven, do the following test:
1.Place the empty dish and a glass of water inside the microwave oven;
2.Close the door;
3.Set the Power Level Selector at maximum power;
4.Adjust the timer to 1 minute;
Note: the oven starts
If during this test you hear any noise along with sparks, turn off the oven immediately.
Any kind of cookware that has this kind of behaviour or is very hot when removed from the oven should not be used in the microwave oven.
EXCEPTIONS:
Glazed ceramic dish recipients contain many water molecules and heat a lot, but can be used in the microwave oven.
If in doubt, contact the supplier of the cookware, and make sure that they are appropriate for microwaves.