[Michael G.]

Originally Posted by sasman29

I use a product called Wet and Forget. Hose end applicator, no scrubbing Works pretty well on my roof up north.

You said it's used with a hose, but could I use it with my power washer?

[KAM+6]

Originally Posted by Michael G.

You said it's used with a hose, but could I use it with my power washer?

No because the ratio of water would not be the same. It is sprayed on and left on, working slowly. No scrubbing or high power.

[DAVES]

Originally Posted by Golfer222

What is the best way to remove this and is there a way to prevent it ?

I would first try a power wash. Muriatic acid works well and is inexpensive-do not get on paint or plants..

[retiredguy123]

I have black stains on my concrete. I like it. It gives a rustic look to my driveway.