You need a dedicated leather cleaner, and not those wipes. Something a bit stronger. Check Autozone/Orielly's and see what they have on the shelf. You're looking for a dedicated cleaner, not a cleaner and conditioner combined. Meguiar's has an aloe based cleaner that works decent. Start there and see what it does. It's really hard to tell you what to buy without knowing(seeing) whats on your seats.
If you don't have any luck, give me a call. I have some stuff that will knock it out pretty easily.