Howdy,
This is a problem? I bought a Lee pot new from their surplus store online. It had rust also. Big deal. You should have seen the junk I melted in there the first time out. I've been using mine for ten years with no problems. Remember that your alloy will be heavier than most anything in the pot, so the rust floats. Now, if you get plugged up with bits of gold, let us know where your alloy is coming from!
Bitterroot