To remove smoky stains from walls brush them with a broom; then wash them over with strong pearlash water, and immediately rinse them with clean water before the pearlash is dry. When dry, give the walls a thin coat of freshly slaked lime, containing a liberal proportion of alum dissolved in hot water. Finish with whiting and good size. Be careful not to apply the size distemper until the lime-wash is dry, as the latter will destroy the strength of the size if the two come in contact while wet.