Why the first attempt is the one that counts
This is written for West Tennessee houses, where the older stock runs to plaster on lath, painted softwood trim and unsealed brick — three of the surfaces that punish a wrong first attempt hardest.
Soot is not dust. It is a fine, dry, acidic carbon residue that settles into whatever it lands on, and on a porous surface it sits in the pores rather than on the face. The instinct with a mark on a wall is to reach for a wet cloth. On dry soot, a wet cloth is close to the worst available tool: the water carries the carbon down into the pore structure, and once it is in there, no later cleaning brings it back out. What was a removable film becomes a stain in the material.
That is the whole of the distinction on this page. Some surfaces will forgive a first attempt that went badly, because whatever you did stayed on the surface and can be redone. Others will not, because the first pass either lifts the residue or drives it in permanently, and there is no second pass that undoes the second outcome. Knowing which kind of surface you are looking at before you touch it is worth more than any product.
The residue also keeps working while you decide. Soot is acidic and it goes on reacting with what it has settled on, which is why polished metal, glass and finished fixtures are cleaned early on a professional job rather than saved for last. Time genuinely matters on those, and it matters far less on a painted wall.
Surfaces an owner can safely clean
Sealed countertops, glass, mirrors, window panes, painted washable trim and doors, metal fixtures and hardware, appliance faces, and finished cabinetry with an intact factory coating. All of these carry the residue on the surface. A dry chemical sponge, sometimes sold as a soot sponge, lifts it off without water and without pressure, and if the first pass is imperfect the second one still works.
The technique is more important than the tool. Work dry, work from the top of a room downward, use light strokes in one direction rather than scrubbing back and forth, and turn the sponge to a clean face constantly. A loaded sponge stops lifting and starts smearing, and the moment it starts smearing you are grinding carbon into the finish. Cut the sponge to expose fresh faces as it fills, and expect to go through several in one room.
Wash only after the dry pass has taken everything it is going to take, and only on genuinely sealed or washable surfaces. Ventilate while you work, wear gloves and a fitted respirator rather than a paper dust mask, and stop if the residue is heavy, oily or greasy rather than dry and powdery, because that residue behaves differently and smears on almost everything.
The one-attempt list
Flat latex ceilings and flat latex wall paint. A flat finish is a rough finish under magnification, it holds residue mechanically, and the first wet pass across it will either lift the soot or set it into the paint film. Ceilings are the worst case because they are where the residue is heaviest and where every stroke shows. A flat ceiling that has been wiped wrong is usually a repaint rather than a clean.
Raw, unfinished or oiled wood: exposed framing, unsealed beams, oiled cabinetry, old heart pine floors that have been refinished more than once. Unsealed brick, stone and masonry. Grout of any kind. Wallpaper, and particularly anything with a textured or fabric face. And anything with a nap, which means carpet, upholstery, drapery and rugs, where a wet attempt drives the carbon to the base of the fiber and beyond the reach of extraction.
The common thread is porosity and absorbency. Every material on that list will accept water and take the carbon in with it, and none of them will give it back. If you are not sure which category a surface falls into, treat it as one-attempt. The cost of being wrong in that direction is that you waited; the cost of being wrong in the other direction is a refinish.
What to do with the surfaces you should not touch
Leave them alone and stabilize the building around them. Get the roof closed if the fire department opened it, because an open roof in a humid month turns a fire loss into a fire-and-water loss inside a day or two, and a soot problem plus a moisture problem on the same porous material is far harder than either one. Turn the air handler off so the duct system stops distributing residue into rooms that never saw smoke.
Do not reach for an odor product. Deodorizers, foggers and scented sprays applied over live residue add moisture and mask a smell that will come back as soon as the product fades, and on the one-attempt list they add water to exactly the materials that should stay dry. Odor in a fire building is residue that is still present; removing the residue is what removes it.
Photograph everything before you clean anything, including the surfaces you are about to work on yourself. If you clean a countertop and then need to show what was there, the photograph is the only record. It costs a few minutes on the day and it settles arguments later.
Where the owner's work reasonably stops
A kitchen with a contained fire, dry powdery residue on sealed and painted surfaces, and no structural involvement is genuinely an owner's afternoon with a box of chemical sponges. Saying otherwise would be dishonest. Plenty of small fire cleanups do not need anybody dispatched, and a contractor who tells you every one of them does is selling a mobilization rather than answering the question.
It stops at the one-attempt list, at heavy or oily residue, at anything above a ceiling or inside a wall, at ductwork, and at any building old enough that a fire has opened up materials worth testing before they are disturbed. Anything standing before 1978 is treated as containing lead paint until a test says otherwise, and plaster on wood lath, resilient floor tile, the mastic under it and pipe lagging of that era are all asbestos candidates. Those are precisely the materials a fire exposes and precisely the ones an owner with a scraper disturbs first.