I have a friend who has this bag in both white and the dark silver color. She's worried about using this bag and getting caught in the rain. She wants to treat the leather with a protectant spray, but can you do this with the white leather.....and what about the silvery bronze leather? I have never treated a leather bag, so I don't know much about this......but I'd be worried to treat a light colored or a metallic bag.......maybe someone here has done this successfully??? Thanks for any help!!!!!