Moisten three soft cloths with lukewarm water, and wring them out well so they are slightly damp.
Rub one moistened cloth over the top of the bar of soap to apply a small amount of soap to this moist cloth. Leave the other two cloths moist with water only.
Wipe a two-square foot or less area of the leather couch with the damp and soapy cloth to apply the soap to the leather.
Wipe the same area of the leather couch with one other moist cloth to remove the soapy residue. Wipe the leather couch with the last moist cloth to remove any more traces of soap and soiling.
Buff the leather couch with a dry cloth to shine it.
Repeat steps 2 to 5 to clean the entire leather couch.