I have run mold frequency in the center in a room for several days. I found no problem or residue but you can put a cloth tent over it but do not block the holes in tube if that is the system you have. My room was empty. You were not specific as to your situation.
Since the machine kills the mold in the whole room, my presumption is that any spores that landed on it would be killed along with the rest of them in the room.
It is my understanding that once you kill the mold, any toxins present in the house can be aired out, vacuumed up, washed away, etc.
Granted I may not be fully cognizant of the issue, as I am not a mold remediation specialist.
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