Believe it or not, use the leather cleaner sold at Moran leather furniture stores. You can get it elsewhere.
Used it on my EB, and did a great job.
Just remember, the trick is to clean leather as seldomly as possible. A wipe down with a wet rag is enough most of the time. A full clean every 2 years, followed by a leather treatment, is all thats required. You will be amazed at the colour change when you first clean it.
Chevs may go, but theres nothing like a HO!
Proud LSUG Member, and 9" Nodular Iron driveline test pilot.