If you can’t find a sufficiently long swab to clean a long and fairly narrow whistle, I recommend a bagpipe brush. They’re not super absorbent but good enough.
When I first got my Carbony G (which I’m still hoping to swap or sell, by the way), I couldn’t find a suitable brush. The flute rod and cloth I use for my MK Pro F were just too wide to fit.
Some convoluted series of clicks on Amazon UK got me to this bagpipe brush. I bought one a year ago when I got the Carbony, and I’ve just bought another from the same seller.
(Amusingly, the seller is “Ladders Direct”, who indeed specialize in ladders. I can only wonder why they also sell bagpipes. Is it that once you’ve finished working up a ladder you feel like letting off steam with a good puff on the pipes? Or is it more that having bought a set of pipes, your family ask you to climb up a ladder if you’re going to play them? Some might say that’s not far enough.)
Anyway, I assume that there must be other sellers of bagpipe brushes in the world and so thought I’d pass the tip on.
How absorbent are those mops? (Every time I’ve cleaned a firearm, I’ve used solvent on a patch.) That could well be a good alternative to what I’m now using: unbleached cotton left over from my vaping days, cut to fit the slot in my recorder’s cleaning wand. That stuff is extremely absorbent, but has on a couple of occasions taken up residence inside the body of a whistle.
The fibers are dense and absorb all visible moisture in a metal whistle. The mop’s dampness evaporates overnight, and when completely dry it can be fluffed a bit with your fingers if needed. Keep a couple spares around so the dry time doesn’t interfere. The mop shown is a brass-core Pro-Shot MP45, 100% cotton.
You can also put a slotted jag on the rod if you prefer to use patches. They work well for lightly oiling the bore of wood whistles.
I think I used to have a piccolo cleaning swab for this purpose-- no doubt it was suggested to me here-- but I might have to try one of the other two. The question is which I can get easier… possibly the pistol mop since all the Highland games are shut down this year… assuming the gun shop within walking distance of home is currently open.