Sulfur dioxide is a foul-smelling, colorless gas that is emitted when sulfur-containing fuel, including diesel and fuel oil, are burned. In its chemical form it is used as a preservative for instant potatoes, wine, dried fruits and applesauce. Sulfur dioxide is also used as a fungicide on grapes after harvesting. Removing sulfur dioxide from grapes is necessary to prevent ingestion of the potentially dangerous chemical.
Pour the grapes into a colander. This will ensure that no stray grapes fall from the stems and land in the sink.
Rinse the grapes under a cool tap. Use your hands to rotate the grapes to ensure all of them are thoroughly rinsed with water. Don't use detergents to clean the grapes. According to Cornell University, using soap to wash the grapes is not necessary.
Shake the colander gently to remove any excess water and dump the grapes onto a piece of paper towel.
Wipe off the grapes with a second piece of paper towel to remove any excess water or remaining dirt and fungicide.