Vacuum the leather sofa thoroughly with a soft-bristled brush attachment. Vacuum both sides of the cushions. Remove the cushions and clean beneath them remove any debris.
Fill a bucket with warm water. Dip a sponge into the water, and wring it out thoroughly.
Wipe the water-damaged area with the sponge, and extend outward from the stains. Rinse the cloth in the bucket as needed, and wring it out before wiping the leather. Cover all areas to evenly break up and evenly blend in the stain.
Blot any excess moisture from the leather with a clean cloth. Allow the furniture to air dry.
Dampen a cloth lightly with olive oil or leather conditioner, and wipe the furniture with the cloth to apply a thin, even layer of oil or conditioner.
Buff the leather with a clean cloth to remove any excess oil or conditioner.