1) High solvent strippers like RenoMat,
2) Glycerin based cleaners like saddle soap and Lexol Leather Cleaner, and
3) Mild solvent cleaners combined with conditioners like Renovateur and my GlenKaren Cleaner/Conditioner.
Each has a somewhat different purpose, and each are applied/removed differently.
For example: You want to remove all of the RenoMat from your shoe once you are done cleaning/stripping the shoe, but you would wipe it off with a cloth, not wash it off with water and a sponge.
You want to remove all of the glycerin from your shoes once you are done cleaning, but you would do it with a clean water rinse using a sponge/cloth.
For a cleaner/conditioner you want to wipe off the excess with a cloth, but let the majority soak into the leather before brushing with a shoe brush.