Hello, Gwen, I'm fairly new to whistles, my cleaning so far has been of pre used instruments, but I would think not very often, unless you are a wet blower.
None of mine have any indication of needing cleaning yet, nothing in the barrel or fipple. If you do see any build up, that would be the time to give them a clean.
I don't think small amounts of deposit would affect the quality of sound much, but it's nice to keep them looking good anyway.
I actually had to use soap & water/dishwashing liquid to get my recently obtained aluminium whistle from an Ebay seller clean.
The fipple can be cleaned out using thin flexible plastic strip, cardboard strip, or a feather - then washed through with a soapy solution.
Hope that's a help to anyone else who finds themself with a 'dirty' whistle.
Having purchased a whistle on Ebay, (that was in a sticky, smelly, filthy state when it arrived), I needed to find out the right way to clean it - so I thought others may be interested in this video too.
{url}https://www.youtube.com/watch?v=cO-VoaTieDE{/url}
