Leather sofas take a lot of abuse. Most leathers protect from water and allow easy spot cleaning. However, over time, leather will soak up smells and dirt that will make it smell bad and look discoloured. Use a steam cleaner to clean the pores of the leather and to provide the deep cleaning necessary to rejuvenate the leather.
Scrub the surface of the couch and cushions with a mixture of 1/2 cup of white vinegar and 1/2 cup of linseed oil mixed into a 3-gallon bucket of water. Scrub the surface dirt off of the leather with a cotton rag. Allow one hour drying time before moving on. If the leather couch is very old, rub it down with rubbing alcohol prior to moving on.
Remove the seat cushions and seat back cushions if possible and place them off to the side. You will clean them with the couch but you will leave them off until everything dries. This will expedite the drying process.
Fill the steam cleaner with warm water and a soap approved for your steam cleaner and for use on leather. In most cases, you will locate a holding tank that you use to fill with the water and soap. However, the exact process differs depending on the type of steam cleaner you use.
Test the steam cleaner brush attachment on a small patch located on the back of the sofa. The steam cleaner should not damage the fabric, but it is a good idea to test. Once you test a small area and feel that the steam cleaner is safe, you can move on.
Place the brush attachment against the top left corner on the rear of the couch. Pull straight down on the attachment until you reach the bottom of the couch. If the steam cleaner does not automatically pick up the water, turn the cleaner to suction mode and repeat the strip with the attachment to pull up the water.
Overlap each additional strip by half to ensure you adequately clean every part of the couch. Repeat the process on the front, sides and cushions of the couch.
Open windows and place a dehumidifier next to the couch to help speed up the drying process. Expect a drying time of 24 to 48 hours.