Items needed to clean interior brick walls include table salt, mild detergent, a sponge and a stiff wire brush. The porous nature of the brick allows it to absorb more dirt than other walls inside the home. Smoke and soot often cause additional buildup on the brick of a fireplace.
Protect the surrounding areas by covering them with a drop cloth or old newspaper before beginning the cleaning process. Have plenty of old towels to sop up any water that splashes when cleaning the brick.
Mix the detergent and salt to form a thick cleaning paste. Dishwashing detergent is one good option for use when making this cleaning paste. After mixing the paste, apply it with the sponge. Scrub the brick with the wire brush, and allow the salt and detergent to remain in place for about 15 minutes.
Use a clean sponge and water to rinse the wall. Rinse the sponge regularly in a bucket of clean water. Change the water in the bucket if it becomes dirty. Continue rinsing until you have completely removed the salt solution. Allow the brick to dry, and check for any of the cleaning solution that rinsing missed. Use a scrub brush and more water to rinse the final traces from the brick..