I've read several of the Shining Monkey threads, but still have a few questions: 1) Does Shining Monkey help to prevent all stains (i.e. from skin oils, lotions, dirt) or water stains only? 2) How many coats should be put on the first time? 3) How often must the vachetta be sprayed subsequently (i.e. every month, each use)? 4) Does the vachetta still stain after developing patina? Thanks for your help!