Soot type decides the cleaning method
What burned determines the residue. A fast, hot fire in paper and wood leaves a dry, powdery soot that lifts with dry methods. A slow, smouldering fire in plastics or synthetics leaves a greasy, acidic residue that smears if you wipe it and needs a solvent-based approach. Using the wrong method sets the stain permanently, which is why the residue gets identified before anything is touched.