Cover the lamp shade with cornmeal.
Place the lamp shade in a plastic bag.
Shake it until the cornmeal comes off.
Fill a bathtub with enough warm water to cover the shade.
Add Dreft or Ivory Snow detergent.
Using a towel, rub only suds in a circular motion against the shade.
Dunk the shade in the water.
Dunk the shade into clean water several times.
Hang upside down to dry.