I don't follow your line of thinking. Any fouling that is pushed into the breech is reburned and taken down the barrel with the next charge. If you use a saliva dampened cleaning patch, it will grab hold of the crud and pull it out. If you mark your rod, so you know when its going to hit the breechplug, you can stop the rod short of it so the crud is not deposited on the plug face. If the jag is formed correctly, so that the front ring is smaller than the rear two or three, the cleaning patch will pull the crud out of the barrel when the rod is withdrawn. Then use a dry patch to run all the way down to the breechplug, and give the rod a couple of right hand twists as if you are tightening the jag on the rod, to wipe the remaining crud out of the chamber, and off the plug. Then withdraw the rod. If the barrel FEELS dry, you are ready to load the next measure of powder; if it still fees wet, then use a second patch to dry the barrel, and pull any more crud out of the chamber.
I like to pump the cleaning patch on the rod as I go down, as this sets the patch in the grooves of the jag, balloons out a little of the patch fabric on the face of the jag, so it can soak up and grab moisture and crud from the chamber. I stop the rod short of the breechplug, unless my experience that day, with the relative humidity at the time tells me that the barrel is not getting very damp, or gathering so much crud that I risk plugging a vent, or flash channel on the gun. One very humid July day, when I was shooting my percussion shotgun in a mail shooting contest, I did have trouble with the barrel being too wet, and I had a hangfire and a missed bird as the result. I fired off some caps, cleaned the barrel a couple of time, blew down the barrel to clear the flash channel and nipples. and dried the barrel out after the clean. The next round went off without a hitch. However, from that point on. I changed my cleaning and loading procedure to deal with the increased ( like 99%) relative humidity on that day, and took greater pains than I would normally have to do on a late fall day using the same gun to hunt and shoot pheasants.
If there is any lesson to be learned here by the less experienced shooter, it is that everything is important, and you have to pay attention, and be prepared to change your loading procedure to fit the temperature and relative humidity. There is not such thing as SINGLE right way to load and clean any gun. The gun is not a Semi-automatic rifle designed for combat use. It is a slow firing and slow reloading muzzle loading rifle or smoothbore. The hardest thing for new shooters to get into their head is that being in a hurry only makes mistakes. Those of us who take our time are simply enjoying the process, and the success we achieve when we do everything right for that day. We can, of course, become complacent, and smug, and that is when the devil will bite us in the butt, too! The difference between the older guys and younger guys is that we old guys expect to make mistakes, and expect to learn something new almost every time we shoot these old style guns. Its part of the fun. Its also interesting to everyone when someone's gun does not fire, as to what is the cause. Everybody loves to solve a mystery, and solving them is part of the satisfaciton of this form of shooting.
This is my world, and welcome to it.