Or, you can do what I do...
Once in a while, I take my turkey burner, a cast iron pot, a big steel serving spoon with holes drilled in it, and a 10 lb ingot mold out to the range, and mine the backstop. You will be surprised at the amount of lead you can pull out.
About an hour's work yields about 50 lb of useable alloy, fluxed and cleaned in 10 lb ingots.