This video shoes step by step my experience of restoring a vintage Berry Kieselstein Cord leather bag, from "Acceptable" to "Excellent" condition.
ATTENTION:
Not every bag is suitable to be washed in the washing machine. If it has cardboard materials in the making, glued parts, or exterior light fabric next to leather, i would recommend hand washing or cleaning with corresponding to the material products only.
With patience and the right products you can achieve great results and enjoy waring your favorite vintage bags.