I'd leave all the cards, and cushion wads, at home.
I dimple the balls in a friends old paint shaker, about twenty at a time, with no medium. You just want to dent them, not smooth them. You can make a shaker out of a reciprocating saw, or sawsall, as well. It doesn't take hours of shaking to ding them up good. The purer the lead the easier they dimple. Some guys dip them in melted beeswax, or SPG cartridge bullet lube. But, I haven't seen much difference using a bare ball. I use wool blanket wads made from old army surplus blankets. I dip them lightly in melted bear grease, and a little beeswax, just enough to get a little on one side, not saturated.
Hungry Horse