After a lot of experimentation with various lubes I've settled on pure olive oil for all of my patched ball shooting. It works as well or better than any of the other lubes I've tried.

I put the oil on a stack of two or three dozen patches and massage it in with my fingers, then wrap the stack in a couple of paper towels and squeeze with my fingers so the towels absorb the extra oil and the patches are almost dry to the touch. I store them in empty musket cap tins.