User blog comment:Darknesslover5000/What happen to Souls who are by Hollows?/@comment-1769234-20100510171932

It only states that a Shinigami Zanpakuto or Kido my cleansed a hollow to travel the Soul Society. Noting that only as of now that a Quincies spirit arrows destroy the Hollow completely as its body is destroy thus not increasing the flow of spirit energy in the Soul Society. As for Hollows killing holows/arrancar and Arrancars killing hollows/arrancars it is unknown.