Private PO box (not usps) is the best way to go in my opinion. If you use DHL or something, you track the package for when it arrives. Then, leave it there for several days or so. That way, if the feds are on to it, they would have to be so committed and interested in busting someone they would have to commit an officer to wait for days - that is a lot of time for just a juice bust, and I can't see them committing that much time to it. At the post office, it's too easy for them to just stall while they call a cop over. Obviously, at home THEY may be the ones knocking at your door, and I don't like playing hide-and-seek.