After much thought(not really) I think saddle soap is the way to go. I use to have a pair of Frye boots in that natural leather look, remember the seventies, and I would regularly clean them with saddle soap, broght them right back to the original color. Use a little water with a rag and get a good paste going and then apply it like you are waxing a car, you will be surprised.
I used to use it too on my Pigskin Dingos.
I had some left in my chest of drawers until about 1999, when my girlfriend moved a load of my furniture, including the chest, over to my new place, and left it on the edge of the lawn by the road, and the garbage truck came by and picked it all up.........DOHDOH