Is your fireplace a mess? Does the brick on the front look like the entrance to a coalmine? Would the scientific community consider it a black hole? Here's how to remove baked-on soot, dirt and grease from brick and stone fireplaces. Add 1 cup of laundry soap flakes to 4 cups of hot water. Then add 1-half pound of powdered pumice, which is ground volcanic rock used for polishing. Hardware stores have it, and so do most jewelers. Then add a half-cup of ammonia. Scrub sooty areas with this mixture using a stiff brush and rinse with clear water. Repeat until clean. And that's the On The House tip for today.