How do I clean soot off my fireplace (brick)?

You can go to a Hearth shop and purchase a cleaner specifically for this. I have also used the following; Begin with a solution of Dawn dishwashing liquid and hot water. Apply to the stain, let it set a minute or two and then scrub with a brush, rinse and wipe dry. Repeat process as needed. • If that doesn't work, try a stronger solution. Add 4 ounces of powdered laundry soap to a quart of water. While stirring, heat mixture until the soap is dissolved. Cool. Then add a half-pound of powdered pumice (volcanic rock used for polishing, it can be found at hardware stores or on the Internet). Then add a half-cup of household ammonia. Mix well. Apply the mixture to the brick with a clean brush. Let it set for about half an hour, then scrub with a brush and warm water. Rinse. (Pretest this cleaner in an inconspicuous spot.  more