I think the Native American Indians were, and are, a group of people who are in tune with the "spirit" world on a definitely higher level than most people! Yes, I think in the right hands, smudging works. I have Cherokee in my blood and a Wiccan sister, so we "smudge" to clear negativity now and then. Whether it actually drives away entities?, I don't really know. This is one of those rare occasions that I think there is a bit more than just "the power of belief" depending on who is doing it. Just my humble opinion.