Clark - Pro Clean
New member
I'm working on a church with light pink brick. The brick is about thirty years old and porous. There are seemingly random groups of bricks that are discolored with dark bluish spots. Some are at ground level and others 30 feet up. Nothing I've tried is getting rid of the discoloration. I've tested some spots with phosphoric acid, sodium chloride and also hydrochloric acid with no luck. Has anyone come across this before?
