Your washing machine & laundry detergent are not designed for properly cleaning the designer fabrics used for furniture. Zippered cushions are designed this way so that the foam or cushion can be replaced when it wears out, not so that the cover can be washed at home. Professional furniture cleaning provides a thorough clean without fading, shrinkage, and damage to the shape or fabric. Furthermore, when you clean just the cushion covers the rest of the furniture will not match the clean cushions.