While it may be tempting to use a power washer for quick cleaning, it is generally not recommended for composite urban outdoor furniture. Composite materials, made from a blend of wood fibers and plastics, can be damaged by the high-pressure stream. The intense force can strip away the protective polymer layer, roughen the surface, and even cause permanent etching or gouging, making the furniture more susceptible to future staining and mold growth.
For safe and effective cleaning, use a gentler approach. Mix a mild soap or a specialized composite cleaner with warm water. Apply it with a soft-bristle brush or a sponge, scrub gently, and then rinse thoroughly with a garden hose on a low-pressure setting. This method removes dirt, grime, and mildew without risking damage. For stubborn stains, consult your furniture manufacturer's guidelines. Regular, gentle cleaning will preserve the beauty and longevity of your composite furniture far better than aggressive power washing.