If soot residue is non-oily (doesn't smear), clean using a lambswool duster. NOTE: Feather and synthetic dusters are not recommended.
If soot residue is slightly dry, use dry chemical sponges to remove gross soot reside. Be careful to not press hard as this can permanently imbed the soot into the pores of the drywall.
Prepare three buckets as follows:
Bucket One (Cleaning Solution) - Dilute your cleaning agent per label instructions. You can add either 1-3 oz of OdorX 9-D-9 or Fresh Wave IAQ Air and Surface Liquid to your cleaning solution for extra deodorization capabilities.
Bucket Two (Waste Solution) - Fill the bucket 1/3 to 1/2 full with clean water.
Bucket Three (Rinse Solution) - Fill with clean water.
Clean the walls using rags or towels using the following method:
Dip the towel/rag in Bucket One, lightly wring it out, and clean a small area of wall (1' x 1' to 2' x 2' area). When cleaning, start at the bottom and work your way up.
Dip the towel in Bucket Two, and then wring it out completely.
Dip the towel in Bucket Three, and then rinse wipe the area that was just cleaned.
If there is any permanent staining or residual odor, you may need to prime/seal the walls and repaint.