I have tiny black spots on my sidding and can not remove them even with powerwashing. I was told by someone that they are caused by the mulch that I use in the ground cover beds. These spots are hard and can not be brushed off, any ideas?
This sound's like it may be artillery fungus. Listen to this call to learn how to remove it: https://www.moneypit.com/audio-q-a/remove-mulch-artillery-fungus-siding.