Green flagstone with spots Tony Deluna 26 Mar 2020 12:37 EDT
Hey Pros, I have this green flagstone.  In the picture it’s wet and you can see the spots on it.
When it’s dry they’re very faint. The customer thinks her contractor splashed stucco on it.
I tried acid and Klenzstone 1 in a small test spot.  I then scrubbed with a small piece of very course
Black strip pad and rinsed.
Absolutely no change, plus when it dries the scrubbed areas are now much lighter and more obvious than the original spots when dry.
Any thoughts guys?

Tony DeLuna