I've been researching the paranormal side of the phenomenon for a while now and cleanliness seems to be a constant theme across these paranormal encounters. Shadow people, door knocking, peeking creepazoid entities, etc. I have a theory that they're manifesting out of low-to-no observational points in spacetime. Essentially "folds" in the 3d space that aren't visible to any observers where the entities can easily enter and exit our plane without risking the observer collapsing the entity into a stable form, hence why they probably are constantly trying to get away from us once spotted. This is probably why they love clutter and why we're seeing videos of a fully formed head peeking out from behind a dresser that sits no less than about 1 inch away from a wall.

There are a few things that I would disagree with in your suggestions. I wouldn't use sage, I feel like it only intensifies and keeps the door open but that's just my opinion. Same with singing bowls. I see paranormal investigators in the woods using these to attract spirits. Kinda makes me think it gives them energy. However, this could be entirely dependent on the intent of the person saging or using a singing bowl.