Q.: A fire broke out in our warehouse but it was extinguished within an hour by the fire department. We were glad to learn from investigating engineers that the walls, which are made of tilt-up construction, are still structurally sound although they are covered with black sooty stains. Is there a good way to remove the stains so that the walls will be light in color? For most of the area a simple cleaning will be satisfactory to restore light reflectivity.

However, we will want to clean some areas near the office well enough so that they can be painted.

A.: Most smoke stains can be removed readily by scrubbing with scouring powder and water. This can be followed by swabbing with a cloth or sponge soaked in a solution of sodium hypochlorite. Workmen should be careful to wear rubber gloves to protect their hands and goggles to protect eyes against splash. The sodium hypochlorite should be rinsed off, especially in the areas where paint will be applied.