Pressure wash i would spray mold mildew remover first
Hi ! I used a product called wet it and forget it . It comes in a concentrated liquid . You put it into a pump sprayed and add water . You spray down the surface on a dry day , and that's it ! It takes a couple of weeks to see how well it works ...I used it on my sidewalks on the shady side of my house that had turned black. My husband tried using a cleaner and stuff broom , that didn't work , then a month later he tried a foaming cleaner , that didn't work either . I saw the wet it & forget it at Costco and gave it a try . At first it looked like it worked a little , but not nearly as good as I wanted . But after a few weeks I noticed that they weren't black anymore ! They were almost back to normal color !!! This year I am planning on using it again as it is also a mild inhibitor . Good luck !
We cleaned siding and a roof with wet it and forget it. You don't wash it off but let it continue to work over time. We also used it on concrete successfully. They were all a mess when we first did them, but stayed clear after use.
Bleach scrub brush
Beach is always a good choice for mould.