I was out on our trail with a buddy on New Year's Day. Snow was up to our knees and temperature -19 C. I used pure neatsfoot oil for my lube on precut .022" patches which turned into grease with the cold. I used my usual .495" soft lead balls in a .50 cal Beck styled longrifle with a 44" bbl. and never had the slightest problem loading. The rifle was satisfyingly accurate! I shot over fifty rounds without wiping.
When I got home, I let the rifle come to room temperature before I cleaned it. I always remove the barrel from the stock and emmurse in my cleaning bucket filled with room temp water and one drop of green dish soap. I think the soap was necessary since I was using oil for my lube, as the fouling, though minimal, was stubborn to remove. My first effort, with just a double patch on the jag in the bucket, didn't get it all. So I attached a .50 cal bronze bore brush and gave it a thorough scrub, followed again with a double flannel patch. This time when I dried it, I found that all of the fouling was gone. So I used the last drying patch, and applied a few squirts of Lehigh Valley lube and then ran it into the bore again. I was surprised to find the tiniest bit of black where the patch contacted the bottom corners of the grooves. When I dry my barrel, I put it in a leather pad in my machinist's vise, so I get a good contact with the bore and enough power to use a tight patch. And LV is a good BP solvent! Probably acidic though!!! HA!
The lesson here: using oil or grease as a patch lube requires a more energetic cleaning regime than just using spit for your patch lube.