Saddle Soap? Where to start with this beauty. Some years ago, when I got my SS Holden ute, I was interested to read the leather care page in the owners manual. Saddle soap was to be used, said Holden back then. Now, after countless trims have been replaced or damaged, it's no longer in their new car manuals. Why is this? It shows how strong the myth is, that even a big manufacturer like Holden got dragged into believing in this product. I still see it recommended by many people who obviously have no idea on the evil it releases into their trim. It's formulated for an entirely different type of leather, namely those used in equestrian activities. Saddles, bridles are nothing like your cars leather for good reason; they are exposed to the elements and need more weatherproofing than any car (even convertibles) should see. It was used in the late 1800's as a leather softening conditioner, but no longer, as better, more modern emulsions have been formulated that soften, penetrate and condition a lot easier
Saddle Soap has an alkaline pH (of about pH 9 to 10). It's important that any leather product is pH neutral, as any level of alkalinity can damage the PU top coat, not to mention help shrink and crack it over time. It's supposed to be a good cleaner, but its effectiveness at even this is also on the block. Its alkaline detergents first need to dissolve its own fat and oils before it can even begin to work on the leathers' dirt and body oils. Plus, they recommend when cleaning to really lather it up, which means any dirt suspended in the lather gets pushed back into the top coats pores, helping bury it in there for a lot longer than we want it.
Finally, while it works away damaging the leathers polyurethane surface, you get more great bonuses; wax and solvents, to firstly seal the leather coating (its going to be getting a bit dry in there) and then degrade it away at the same time. This product is an urban myth in the benefits it offers automotive leather, and in our opinion it should not be used anywhere in your car.