Spit as a lube works great for target shooting, when you'll shoot almost as soon as the gun is loaded. But it will definitely dry out if you leave the gun loaded over time, and rust will be an issue as well. My drill for target shooting is to place the cut patch in my mouth while measuring and pouring the powder, then place the patch on the muzzle with the ball on top. I've also used some of the commercial lubes, and they work, too, but the last time I did a comparison, ten rounds with lube and ten with spit, the spit-lubed balls printed higher on the target. I'm sure Pletch has some research on the matter.