I don't buy rubbing alcohol. The Isopropyl Alcohol I buy here for less than $1.00 per quart, is 91% alcohol, and evaporates every time. I have denatured alcohol I bought for a paint thinner, but I generally don't have to use that much more expensive stuff to clean the barrel.
To answer Gmww's question- I clean between shots, depending on the temperature and relative humidity, using either one or two patches, with my own moose milk, and then follow with one or two dry cleaning patches to dry the barrel back to metal. There will be some small amount of residue in the gun, but I don't see much, if any, change in POI when the next shot is fired.
[Just a thought: I find that most changes in POI from the first to the next few shots are due to poor bedding in the barrel mortise, and sometimes, poor bedding of the Tang in its mortise. If those bedding issues are resolved, I can expect the consecutive balls to hit very close to the same POI. My rifle has been glass bedded at the tang and breech because of a crack in the stock there, that could only be mended by glass bedding the wood. I have no problems with a change in POI from one shot to the next -- a pleasant surprise and discovery that has appeared again on several other rifles I have, or have worked on for other shooters.]
I "read" the cleaning patches as I pull them off the jag, to decide how much crud is in the barrel, how much as been removed, and HOW DAMP the barrel is from relative humidity. That is how I decide whether to use one or two dampened cleaning patches, and one or two drying patches. I use both sides of a cleaning patch( I am CHEAP) unless the first side is so wet and damp its slick in the light.
My rule is, " When in doubt( that you got all the crud/moisture " out "), repeat!" The barrel tells me, when I push the next PRB down it, whether I made the correct decision, by how smooth, or jerky, is the effort to seat the ball down on the powder.