The best way I can think of to get the lube off, would be to perhaps toss them in a brass tumbler for a few minutes. Failing that, a wire brush and some time and elbow grease ought to do the trick.
As far as re-lubing them, that's a bit more work. When I used to cast them, I made up a batch of my own wax lube, poured it over them in a shallow pan, let the wax cool a bit, then picked the bullets out and pushed them through a hole in a piece of wood to get rid of the excess lube.