Coat the smoke stain liberally with baking soda. Leave the baking soda on the smoke stain for 15 minutes to absorb soot.
Vacuum the baking soda and absorbed soot off the sofa’s upholstery using the machine’s crevice attachment.
Dampen a white rag with 1 tsp. dry-cleaning solvent. Tamp the blemished portion of the sofa to eliminate the remaining smoke stain.
Continue tamping the smoke stain with solvent until the undesirable dark blemish disappears. Moisten the rag with additional solvent if the smoke stain is severe.
Blot the previously smoke-stained portion of upholstery with a towel. Absorb any excess dry-cleaning solvent lingering in the upholstery. No rinsing is necessary with dry-cleaning solvent.