Use Saddle Soap. It softens leather. You can make your own with this recipe Here is a recipe to make your own saddle soap which will soften leather and remove dirt. To make around 4 pints/2.3 liters * 2 pints 16 floz/1.5 liters water * 24 tablespoons soap flakes * 8 floz/225ml melted beeswax * 4 floz/115ml neat's-foot oil Bring the water to a boil in a large saucepan, and then reduce to a simmer. Gradually stir in the soap flakes. In the top of a double boiler, heat the wax with the neat's-foot oil and stir to combine. Remove from the heat and add to the soap solution. Stir until thick. Transfer the soap to small containers (old shoe polish tins are ideal). To use, apply to leather with a wet sponge, then buff until dry with a clean soft cloth. Caution Neat's-foot oil is flammable; use with care. It might also darken some types of leather or make them less receptive to regular shoe polish, so test on a small patch of leather first.