Now, that's interesting. I had not heard of these before. They look sort of like short lengths of butcher's twine.
Cleaning "loops" are under-appreciated these days. I like that rod you show in the photo. I've made a couple of wooden rods with slots like that. They aren't hard to make... Shave a little flat on opposite sides of the rod, drill a series of closely, spaced holes, cut out the waste with a pen knife blade, and clean it up with a folded bit of sandpaper. Ned Roberts described these in The Muzzle-Loading Cap Lock Rifle: "The target rifle requires both a loading rod, or ramrod, and a cleaning rod in order to obtain the best accuracy. Years ago these were both made from tough, straight-grained hickory, white oak, or other close-grained, tough wood... The cleaning rod is made of the same kinds of hardwoods, somewhat longer than the loading rod, one end having a small knob with a square under-cut, and a narrow, tapering shank [exactly like a jag]... to hold square or round cleaning patches. The other end should have a rectangular slot about one inch long by 1/8 inch wide cut lengthwise in it to hold the dampened patches for cleaning the bore after each shot" (p. 69-71 in the 1952 edition). I have heard these called "wash rods." also.
You can whittle the jag on the other end of the wood rod to any size you want for those odd, old-time calibers, although you might have to reduce the overall diameter of the rod.
A loop like that with a strip of rag in it (or a cleaning wick, I suppose) will do a good job of cleaning the bore, and is pretty forgiving of bore size. It also works well for preliminary cleaning of a very dirty, rusty barrel. It is my belief that a species of devil lives down deep in the bores of neglected muzzleloaders. I call it the "Patch Demon." The little bastard will grab and hold a snug-fitting patch on a jag down there in the breech, and next thing you know you have a real chore on your hands getting it back out of there. You might end up posting a "stuck jag" thread here on the forum. Using a patch or cleaning wicks in a loop like that is a good way to start if you have to clean a badly neglected barrel, for defeating the Patch Demon. It works pretty well for cleaning a good bore, too.
Thanks for posting! I had not heard of cleaning wicks, but they look as if they would work well. Leave it to the Germans... The folks who gave us Ballistol.
Best regards,
Notchy Bob