New ghosts clue idea, when going into a house you can come into contact with various substances, though the colors, textures, and consistancy are sometime looking like normal food, sometimes it is ectoplasm and you need a vial to scoop it, but be careful dropping a vial can make it break. Once the substance is extracted in the vial you can return it to the truck substance analyzer which will spin the bottle around and analyze if it is ectoplasm or not, but that can take time so you may want to keep hunting while its analyzing.