How do you treat and condition vintage Gucci interior leather?

I am a collector of vintage gucci bags, and the ones from the 80’s are notorious for flaking. The leather is a soft kidskin leather, with some texture, and I don’t want to use the wrong conditioner. Does anyone know a natural leather conditioner that will not harm soft delicate leather? I want the bags to keep their moisture so they do not flake. Thank goodness Gucci has now started using fabric for the inside!