I have had a lot of horse tack and I used to use Turf Soap.(was like a big jar of white pudding) Everybody at the track had a gallon of it. Cleaned all leather and conditioned it at the same time. Now it is no longer made so I use Liquid Glycerin which works the same. Spread generously while rubbing to clean. wipe dry with a clean towel. After it dries in a couple of days or so add a few drops of Neetsfoot oil. I have 3 old strops that cleaned up real nice this way and 1 thick one I had to do twice before adding neetsfoot. Stay away from anything that has wax in it like some saddle soaps and products made for boots.