I use Loving-My-Bags on the vachetta on all of mine. It does darken it slightly, but not much. Also, it still allows for the natural darkening of the patina, too. I swear by the stuff because I've had my mono bags out in the rain and not one has water spots on it after it was treated with it. I wanted to leave it natural, but decided that I'd rather have the beauty of the bag with a nice, spot free patina than have them look dirty from use. I bought them to use, not keep stored away. I do still store them in the dust bag and keep them babied when not in use, but I'm so glad I treated them!