Okay, I am washing an old (1902) wood house with blue paint and brick around the bottom. It does not have black mold, but rather green algae… I guess that is what it is… Uh, at least reasonable sure… So, what is the best way to get it clean without taking ALL of the paint off? I did all of the flat work today… bricks and concrete. Tomorrow is the house and garage. The green stuff came off of the bricks fairly easy.