1. Dust sweepings is actually a good source for material to use in a remote when you have a lack of more specific material. Given that you can not be 100% sure if the intended target is in the dust sweeping you took, take notes and monitor any observable changes in the target. If nothing has changed after a week, then it could be either due to the sample does not contain the target in question or the frequencies are not correct. You either than have to decide on a new sample or a new set of frequency programs. It will take more time to find a winning combination, but it is doable. I would recommend that you take many samples from various locations, and just stack them into one remote. You can fit quite a few in there.
2. What I did was go get 2 coffee filters. I used one to go around my place scooping up dust and mold etc wherever I thought it was, and the other I left pinned to the wall of the worst spot for a couple of days. Then I used some of those filters in the remote. This was a while ago, and I can't remember exactly which frequencies I used, but it worked
For more information please check this link: