To remove black soot stains from a wall, vacuum up any leftover soot, wipe the area with a dry sponge, dab rubbing alcohol on the stain and wash the area with a soap and water solution or a soot cleaning solution. Dry the wall completely.
Hook an upholstery attachment onto a vacuum, and use it to suck up as much soot from the wall as possible, being careful not to make scuff marks. Using a chemical dry sponge, wipe remaining soot from the wall in sweeping downward strokes rather a scrubbing motion. Repeat this step with a new, clean sponge before dabbing a clean cloth with rubbing alcohol and blotting out any remaining soot stains.
Next, create a solution of 1 quart water with several drops of mild dish soap, or use 4 ounces of soot cleaning solution mixed with 1 gallon of water. Dip a sponge into the solution, and begin wiping down the wall, working with small areas at a time to avoid spreading the soot. Rinse the sponge frequently to aid soot removal. Wipe down the wall with dry towels, using downward strokes again to avoid streaking. If any soot is visible on the towels, continue to clean the wall with the solution until the towel dries clean.