I don't do anything in particular for cleaning in rituals (except maybe a deep breath beforehand), but I use certain incenses at the beginning of some rituals to harmonize and tune my and/or others' bodies for the work at hand. If something comes along that I don't want there, I just tell it to go away, let the forces I work with take care of it for me, or connect with it to find out what I am supposed to learn from their presence.
What I've learned about smudging through practice is that it actually calls spirits and harmonies to come, spirits that you want present and that it is these spirits that do the job of clearing anything unwanted in the area by the process of disbursement.
Diavanii Regina