ravenest
I just found out that it was from LMD's book "The Magick of Aleister Crowley" p.55
It says "The LBRP should proceed any magickal working or divinationary exercise. It is the magickal equivalent of cleaning, vacuuming and dusting the temple before operating. … The opportunity for magician to create magickal environment."
Really ? LMD uses a k in magical ? Crowley would scowl at that
I would prefer the analogy of the leaf blower.
The beginning Kabbalistic Cross should do the same for yourself. If you invoke the 'light' in it should dispel the gunk out, then 'swoosh' it out of the circle. The 'cleaner' needs to be clean first.
Of course, waving your hands around in the air and vibrating names isnt going to do the complete job .... but it may stimulate a larger process of 'cleaning out' on other levels , if you keep practising you will come to it - there was a good reason why Regardie recommended 'psychological practices/treatments' as well as magical ones .