I used Windex with Vinegar extensively in the past- really melts down blackpowder crud. Another great cleaner is Simple Green. But for swabbing between shots, Cayugad's 50/50 mixture of summer washer fluid and iso alcohol is the best solution out there. Barrel is clean and dry in short order - ready for the next charge to be loaded.

I still, however, use the Simple Green for soaking the breech plug back at the shop; andapply it to a Q-tip for cleaning some of the little nooks and crannies of the rifle. I also swab with Simple Green after the last shot of the day, and let it soak in on the way home.