I was taught a method that sounds counterintuitive, but, works. Take a clean cloth or sponge well wrung out with clear water. Dab the spot from the center out, blotting with a dry cloth after the sponge. It works. Then, after you've let it dry completely use a good leather cleaner and conditioner.
Have you tried saddle soap.
Try Dubbin to polish
Idl, here's a popular video that has the answers to water on leather!
https://www.youtube.com/watch?v=Mx2DG5Dgmpw
I was taught a method that sounds counterintuitive, but, works. Take a clean cloth or sponge well wrung out with clear water. Dab the spot from the center out, blotting with a dry cloth after the sponge. It works. Then, after you've let it dry completely use a good leather cleaner and conditioner.