A leather sofa is a major investment, and keeping it clean prevents the leather of the sofa from losing its luster and color. Mildew will attack a leather couch if it is wet or kept in an area with a high moisture level. The organic tissue of the leather is the ideal place for mildew to grow. Removing the mildew from your couch properly will prevent its return and prevent any damage to the surface of your sofa.
Mix one part white vinegar and one part water in a bowl. Dip a rag into it and wipe down the surface area contaminated by mildew or mold to remove it.
Mix together one part rubbing alcohol and one part water in a spray bottle. Shake the bottle to mix.
Spray the rubbing alcohol mixture onto a dampened cloth and wipe the surface.
Move the couch out of direct sunlight and place a rotating fan before the couch to dry it.