You could try saddle soap. Get the version made for white leather, has a white lid and states it’s for white leather. Use a clean, wet sponge, work it into a lather. Let the lather dry. Then buff it off with a clean towel you don’t intend to use as the “for special” hanging in the bathroom. Then use liberal leather oil. I like the Aussie stuff, heat of your hand warms it and pushes it into the leather. Makes your hands soft for a few days too, so bonus. but whatever you prefer as long as you oil it. Neetsfoot is also really great with leather. I prefer the pure oil to the wax oil, but for white leather you may want to use the wax. Saddle soap dries out leather, and you could see cracking if you don’t add those oils back in, but it should take that off the top with minimal effort.