Unfortunately that looks like it may be color transfer. It's not cleanable and won't come off. If you do a search using the keywords "vernis" and "Color transfer" you'll see lots of threads about it. It's really important never to put any lose receipts or papers in your purse when you're carrying anything that is vernis. Or setting it on a newspaper or magazine. The print transfers literally into the patent and its permanent. It can happen with any dark material too, and that's kind of what this looks like (jeans are notorious for this, but any dark lined purse can do it too). You might try a damp cloth just in the hopes that this is just dirt. But just barely damp - not wet. I'm so sorry that happened to your pretty wallet! HUGS!