How in the world do I clean the black streaks off of our white gutters? The vertical lines are resistant to pressure washing, bleach and a scrub brush.
I remember a few years ago someone said there was a product in a spray bottle that would remove these stains. All you had to do was spray it on and wait a little while then spray with your water hose. All the streaks would then be gone! I can't remember the name of the product. I think they said you could buy it at a home building big box store.
Help! I can't find the product...