A plate may become stuck in a ceramic bowl because of the way you stored it in your cupboard or because someone accidentally stacked it that way when clearing the table. Using a butter knife or other tool to try and separate the dishes is not a wise idea. Often the tool chips, scratches or breaks the bowl or plate while you are using it in an attempt to separate the dishes. Other methods may be more successful without risking damage to either dish.
Place the ceramic bowl and plate into the freezer section of your refrigerator. Leave it in there for an hour or two.
Remove the ceramic bowl and plate from the freezer with oven gloves or potholders.
Set the ceramic bowl upside down onto a soft, folded towel. This provides a soft place for the plate to fall.
Tap the bowl lightly with your fingertips around the base. You will hear the plate drop onto the soft towel within a couple of minutes.
Place a stopper in your kitchen sink.
Fill the sink with 3 or 4 inches of hot water, but not enough to get into the ceramic bowl.
Immerse the ceramic bowl into the hot water with the base of the bowl down .
Pour icy water on top of the stuck plate with a pitcher. The heat causes the bowl to expand and the cold water enables the plate to contract. This causes the plate to loosen so you can remove it.
Don't turn the bowl upside down until the folded towel is in place. It may slide out on its own when you tip it over. Another method to try is immersing the ceramic bowl and plate into hot, soapy water for three or four minutes. The soap acts as a lubricant and may separate the dishes.