I use a pumpkin based soap which is very effective with my leather shoes, I usually wax them after the washing procedure. The soap looks kinda like this: 

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/3cn19.jpg

I believe this soap is from a Mexican brand, but I'm sure you will be able to find something similar if not the same. I doubt it'll be hard to find.

 1. Add a couple of drops of water on the paste, so it can become soapy
 2. You can use an old toothbrush, and gently get some of the paste on it and start brushing your shoe(it's better if you've dusted off the shoe)
 3. Once the shoe has been brushed, with a dry and clean cloth remove the excess of liquid and soap
 4. Once it's dry your shoe is ready for waxing.
 5. Dispose of any excess water on the paste and let it air-dry before closing it.