I’ve always like “patina”. It’s just so wabi sabi.
Waxing, varnishing, and coating brass whistles 
I’m with the old school…let 'em “patina-ize” and just keep playing. I like to see whistles that are obviously played. Have you seen Joanie Madden’s O’Riordan up close on YouTube videos? Talk about well-worn.
If your chemical excretion is that potent, nothing’s going to be of significant help and you’ll just have to keep polishing and re-coating, so just go with the natural flow of your brass whistle aging and developing character.
Oh, that old wive’s tale is verifiable poppycock. In fact, the hair that grows on your hands makes for a better grip on the whistle.
Dang, my five-hundreth post turns out to be an off-color comment having nothing to do with whistles. That’s life at C&F, I guess.
Inspired by this, I just treated my ucky Dixon Trad brass to a Simichrome polishing, followed by two coats of Meguire’s #26 carnauba wax. Now it’s as clean as a whistle (I had to say that!), and sparkles like the treasures of Tutankhamen. And the wax seems to work. Normally, after 10 minutes of play, my fingers would have it well on its way to antique status. But there’s not a mark so far, and I like the silky sort of feel. Thanks, Mr. Whistle! 
Your welcome MT. I always try to find several answers to suit different tastes. (Pssst! I love your “Rana Regis”! [Frog Prince] Icon)
Yes, and it makes it look like I play them a lot.