We discovered a leak from the chimney down to our brick-in fireplace. The brick on the inside is now dark brown and white. I have tried drying the brick with a heater but it seems to be making it worse with the white. I believe the white is efflorescence. Other than an efflorescence cleaner how can I get the brick to look the same as the others. We are trying to sell this home and now it has this ugly spot on the fireplace.
Before you consider cleaning the fireplace, you need to make sure to fix the leak. Chimney leaks like this are no uncommon. The way to fix them is to make sure the flashing is properly installed and not just coating with tar. You need both flashing and counterflashing and you will have to go through roofer to install it. Once the leak is repaired, you can try to remove the mineral salt deposits with a white vinegar and water solution. You can also clean the brick with a wire brush. Good luck with your project!