If you simply want a stranded twine, you can go to the hardware store and buy jute twine, Cut off a 4" strand, untwist the strands and fray out the individual strands to make a nest of hair like fibers. You can also go to a hobby store and buy a ball of hemp twine to make the same nest of fibers. The best of course is tow from flax. The Woolery has Tow ( Flax Tow | Tow Fiber - 1.0 lb. | The Woolery ) but the minimum order is a pound and that will last a long time. For initial experiments, use the basic twine from the hardware store or hobby shop and unravel your own.
If you want to buy some already unraveled, the Townsends has some. Tow – Townsends (The Hemp tow is sold out.)
Great for cleaning the piece by using a period correct tow worm as well. I get mine from Turkey Foot traders along with their country bacon for making split pea or bean soup.
I've been using the fibers of unravelled hemp rope rolled into a ball. Works well enough, and you can buy 1/4 hemp rope pretty much everywhere.
It just smolders after leaving the barrel, and if you use a large enough ball it won't travel very far, so you can just stomp it out as you walk by if you are that concerned.
@Elgatodeacero, The Tow offered by Turkey Foot Traders, that you reference above is hemp tow. Nothing wrong with using hemp tow, but a ball of hemp twine can be found at most hobby stores such as Walmart's craft section, Michael's, Hobby Lobby or many others. The only difference is that you have to unravel the strands of the twine to make up the individual hair like strands to make your nest to use as wadding. Jute is a good base twine to use as well. Sisal, not so much.
I have become very fond of tow wadding in my smooth bores. I use sisal rope for my wadding material. I use a paper card over the powder then a walnut sized ball of tow lubed with mink oil then my ball or shot then another ball of lubed tow on top. This is all I use except for the SkyChief load.