The composite deck had been in place for 10+ years and never cleaned. It was it pretty bad shape!! We used the Corte Clean on a cloudy day so we could allow it to soak for the recommended time without drying out. The deck isn't perfect, but the difference is AMAZING. Very little scrubbing, very little effort and the deck looks so much better. We truly were not sure what to expect as this deck was in bad shape. Still a little more work to do, but I believe with another cleaning this Spring, it will look GREAT. Very pleased with the results. FTM: Dover Delaware