ghosts as you call them would be passed on enities that are stuck in what is called the astral plane, also known as the 4th dimension.
if dealing with these entities tell them to go to the violet light, not the white light. there is technology in the astral plane that has copied white light and cleanses the energy and sends the entity into the astral and into another incarnation.
violet is best.
"Each soul in entering the material experience does so for those purposes of advancement towards that awareness of being fully conscious of the oneness with the Creative Forces."