Many strong food smells can be removed by placing a mixture of 3 cups of water, 2 tablespoons of lemon juice and 1 dozen whole cloves in the oven and bringing it to a rolling boil. Permit the mixture to cool in the oven without opening the door. The generated steam will help to remove the odor.
For mild odors, try warming a cup of water with a few drops of lemon for approximately 1 minute.