I built a completely pressure treated deck five years ago and stained with Sikkens. It's on the north side of the house and now is very dirty---some black spots (mold, I guess) on the rails, etc.
What's the best way to clean this without damaging the wood or stain (the stain is holding up very well). I've been told pressure washing is too tough and a no-no with pressure treated. TSP? Some of those deck cleaner/brightener products?
Thanks.