Though traditional chalkboards are a dying breed in the age of interactive whiteboards in the classroom, they still exist, and as long as they do, felt chalkboard erasers will still accumulate a ton of chalk dust. Traditional methods of cleaning erasers--old-fashioned eraser clapping--still work, but nowadays other methods can help you effectively clean a chalkboard eraser.
Clap and Vacuum the Eraser
Pound the eraser against the side of a hard surface. Perform this activity outside so that the dust particles do not cling to surfaces in the room like clothing, furniture or interior walls and you do not aggravate anyone's allergies.
Rub the eraser against a white towel. Remove dust particles and dirt by sweeping the eraser against the towel.
Clean the eraser using a hand vacuum on its lowest setting. Remove the dust particles by sweeping a portable hand vacuum across the soiled surface of the eraser.
Wash the Eraser
Fill a shallow bucket or container with warm water.
Dip the eraser into the water to remove the dust particles. Use your fingers to remove any stubborn debris.
Set the eraser on a towel and allow to dry. Make sure the eraser is totally dry before you use it again on the chalkboard. This method of cleaning is effective, but it will take several days for the eraser to dry.