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.