I have a Timber Tech deck that seems to attract mildew in all the little faux wood cracks and crevices. I knew it wasn't maintenance free but if I could go back and pick another decking material I would have opted for a more expensive and harder wood or more mildew resistent composite material. That said, I found Corte Clean a few years ago when I was on the Timer Tech site and they recommended it so I tried it. It works as promised and DOES do a fantastic job at removing the mildew. Takes some elbow grease to clean though and you need to work in sections if you have a large deck. Seems to help prevent the build up of mildew especially in areas of my deck where rain water just won't drain and has to rely on the sun and evaporation unless I get out and squeegee the area. Definitely worth the cost and it's pretty easy and not harsh to use. I don't have a photo but it would be difficult to see any before and after as I don't let the mildew get so bad as to see a "night and day" difference. You'd have to be on the deck to really see the cleaning results but that's what it's for...maintenance. Not to wait until it gets so bad that your deck is blackened by mildew. At that point you'd probably need professional services or at least a pressure washer before using this stuff....