Have you heard the phrase, "oil and water don't mix"? You may not associate that maxim with the greasy stain on the your garment, but that is the basis behind dry cleaning. Dry Cleaning uses organic solvents to break down greasy and oily stains in ways that water simply can't. Natural fabrics, such as silk and wool, will distort, shrink and even lose color when washed in water. Cotton and linen, if not pre-shrunk before manufacturing, will too. Synthetic fabrics, like polyester, are notorious for holding oily stains.