Remove as much dust as you can, dunk it in warm water until it becomes more pliable. Then while still wet, lather up one hand and apply. Allow it to remain for a few minutes, then wipe with a sponge that squeezed enough so it's not dripping all over. Rinse it lots under fresh running water, squeezing the soap out. You don't want to be reapplying as it will be dirty. When rehydrating a saddle I tried using a spray bottle. The leather was soaking it up as fast as it when on with negligible difference. The next day I set it out in a good downpour. Ah, it was soaking wet but the leather was pliable. The next day, soap was applied to the now damp leather which lifted a tremendous amount of dirt. The saddle was left a few days and then given a good oiling while the leather was barely damp. A few days later a light buffing with a soft cloth which gave it a beautiful mellow sheen.