Veelay

So, I've been having a bit of trouble figuring out an efficient way of harvesting and transporting Karbonite. I'd like to mine it from the Mun or Minmus, and bring it back to Kerbin. Can anyone give me some tips? Is it better to refine on the ground or in orbit? Better to transport Karbonite itself from the moons, and refine on Kerbin, or to refine it in orbit around the moons before transport? I just can't seem to figure it out! It's just hard to make a good delta-v profit from the process.