Washing powder research. Computer analysis used in washing powder research. The screen lists the substances used to contaminate the cloth that is partially covering the computer keyboard. The cloth is to be washed in detergent to test its ability to remove stains without damaging the material. Detergents work because their molecules are soluble in water and in grease. During the washing process, a detergent molecule attaches itself to a grease molecule on the cloth and carries it away into the water.