Do Not Use Salt; Try Rice Instead by Jennifer Scelsi of CSI: Paranormal

I know I know: everyone is telling you to put a line of sea salt around the outside of your home, or put it on windowsills and in small bowls throughout the house.

However, if you already have a ghost inside your home, putting salt around your home is the last thing you want to do. The theory is that spirits can't cross a line of sea salt. So if you already have a ghost inside your house, then by putting sea salt around the outside of your house or on the windowsills and by doors, you are trapping the ghost inside your home and preventing it from leaving! Not the result you want. 

Instead of salt, use rice. Sprinkle a line of rice around the outside perimeter of your home, getting rice as close to the foundation of your home as possible. The theory behind this is that rice will lure the spirit out of your house. I have not tried this myself, but I have heard from people in the paranormal field that this can work. 

Once you are sure the ghost is gone from your home, then it is safe to put a line of sea salt around the outside of your home to prevent any more negative ghosts or spirits from entering.