Take a large sized bowl or a wide container and put 10 charcoal briquettes in it.
Place the bowl containing charcoal in the refrigerator. The charcoal briquettes will absorb the smell in the refrigerator.
After a couple of months, your fridge may start to smell again. This is when you need to treat the charcoal briquettes, since they would have absorbed enough odor and start smelling themselves.
Take the charcoal briquettes out of the fridge and put them in a cooking pot.
Place the cooking pot on the stove and let them heat for several minutes over medium high flame. When the charcoal briquettes are heated thoroughly, the smell absorbed by them will be neutralized. Let the charcoal cool completely in the cooking pot.
Meanwhile, thoroughly wash and dry the bowl that held the briquettes in the refrigerator. Put the cooled briquettes back into the bowl and place it back in the fridge.