Has anyone a good recommendation how to
foster your TW?
You know it’s almost hopeless to clean it with a tissue made for silver and similar materials. After half an hour playing it looks just like before. Though I know quite a few people like this old, used-looking surface. But I want it shining (and I don’t like it wrapped into this, uh… I’ve got no English dictionary with me right now)
Any tips?
All you can do is buy another whistle that has been painted, I think. I don’t know how to polish the other kind. 
If it’s a brass whistle, you should be able to keep it polished with brass polish. I have a nickle-plated whistle, which I have been unable to keep polished, although over time it’s slowly becoming brightly polished around the finger holes… (It went from new-shiny to darkened to hazy to mirror-finish… my fingers both react to the metal with sweat & oils -and- serve as a very slow method of buffing to a mirror-finish… 
)
If you really wanted an instrument to be always-polished (because they will retarnish with just a few hours playing), you’re going to have to have it lacquered, which may change the tone.
–Chris
Here’s what’s worked perfectly for me over the years with metals. Wipe down with quadruple ought (0000, super fine) steel wool and finish with a jeweler’s cloth to polish. Simple, fast and will bring a like new look. Some boarders have cringed at thought of steel wool; but it works great and does no damage. remember must be super fine 0000 only!
Sorry if this posts twice. What’s worked perfectly for me on metals over the years is a wipe down with quadruple ought (0000, super fine) steel wool and finish polish with a jeweler’s cloth; brings a wonderful like new look. Some boarders have cringed at the thought of steel wool, but it works great with no damage to metal. Just remember it must be 0000, super fine.
It might help to note that 0000 steel wool is used to smooth the surface of tarnished knives, newly finished furniture, etc. This is not brillo we’re talking about. Good suggestion, I may try that.
–Chris
I take it that TW means Tully Whistle.. I use a 2 sided jeweler’s cloth to clean mine. The red side has jeweler’s rouge on it which cleans away tarnish, then the yellowish side buffs it up. Works like a charm, and ErikT recommends this. Even as fine as 0000 steel wool is, I’d hesitate to use it on that mirror finished silver surface
Paul - I’ve used the steel wool/jeweler’s cloth method on brass and aluminum; haven’t tried it on my Tully yet; but I will experiment and post back. Philo PS - I have also used the 0000steel wool to successfully remove stains (with a chrome polish) from custom blades as I also collect custom knives/swords. Have a wonderful honeymoon. best regards, Phil