My house is about 60 years old – Central Calif. Water penetrated the chimney through some cracks that developed in a couple courses of brick. The water traveled down the chimney and came out in the living room, flowing down the front of the fireplace. The living room fireplace brick is now stained with what I’m assuming is lime from the mortar (the stain is white-gray white).
The stain won’t come off by rubbing, scraping or using conventional cleaners and solvents. Any ideas on other things to try? If your answer involves more caustic solutions should I hire someone rather than trying it myself?