Sent by CynthiaEditor: Try adding a scoop to hot water along with a little vinegar. If it bubbles, then the baking soda is still active. I wouldn't use it for baking since it's been absorbing all those refrigerator odors, but it should be good for cleaning and scouring!
Readers, have you had luck using expired baking soda for cleaning?
(Image: Elizabeth Passarella )