I cannot tell you the number of times I’ve had serious magicians come to me regarding a room with extreme negative energies that they just cannot get rid of. Usually, its a bedroom, or the room in which magick is performed, and for one reason or another, extremely negative entities end up finding their way there (but only in that room, never through the rest of the house). They say they’ve tried everything they know: burning sage, doing the LBRP nonstop, etc., and it never helps anything.
The first thing I do upon walking into a room like this is to do the one thing they seem to never consider: I remove all articles of furniture from room, and sweep or vacuum the floor. Going off of my “a polished turd is still a turd” theory, no matter how many times you hippie out on the sage, the cobwebs, dirt, dust and grime are still there, much like putting a band aid on an infected wound. After performing this one act, the client almost always notices a marked difference in the energy, often describing it as a “flat, peaceful energy” like a freshly wiped chalkboard.
From there, I open up all the windows and doors to the room, and encourage air flow as best I can. Only after that do I use sage, and other forms of protection (with windows and doors remaining open!), like runes over the doors and windows.
In all my times doing this, I have never once had this fail to solve the problem of a “haunted room.” Remember, a house is like an organism, not just a collection of 2x4’s and plywood. If it has an infected wound like that, you must treat it as such. Clean the infected site, promote positive air flow, then dress it properly.