How to remove these stains?

[jaykay]

Best way to clean off these stains? I read ammonia, soap, and salt, but not sure if anyone has any experience with this? Our glass cleaner says for masonry aswell not sure if that would work?

 

[bholler]

Best way to clean off these stains? I read ammonia, soap, and salt, but not sure if anyone has any experience with this? Our glass cleaner says for masonry aswell not sure if that would work?

View attachment 305206

My suggestion would be an alkyd primer and paint after wire wheeling off what you can get

 

[jaykay]

My suggestion would be an alkyd primer and paint after wire wheeling off what you can get

We have a chimney crown repair coating by ChimneyRX on the crown would that damage it? Could we just put more coating on top? Or is that dangerous