my momma is a quilter, so i can get oodles of free patches. i just need to cut them to the right size, start the ball in the middle of the patch so the top is just at the muzzle, then i take my patch knife and cut it. you can also soak them in olive oil and wipe off the excess if you like having your powder go off. i found that the lubed cotton patches from Dixie Gun Works are great, only drawback is they smell like that medicated creme stuff you put on sore muscles or sprains, called "bengay" and i have no idea why. it's kind of like a very intensely minty smell. it's fine by me, they work great! the cotton ones without the stripes load easier, and the pillow ticking ones are a little bit harder to load. i keep a handful in my leather ball bag with the round balls. works great! another thing to try is to use cotton cleaning patches. use a patch knife to trim off the extra material at the muzzle. they load easier than the pillow ticking.
i have heard of mountain men using stuff like grasses, bark, tobacco, leaves, and other materials like that behind the ball to form a gas seal. i think a patch will do a better job because the spin will be imparted on the ball by the rifling.