What is the minimum amount of dust that can be left on a wall before it adversely affects primer application? If it has to be completely free of dust, how do you get it all? Taking a damp rag over the wall seems to be the way to do this based on my own research, but then you have to rinse it wring it out. This dirties up the water which just means more particulates would end up back on the wall as dust after the water evaporates. Plus, going over all walls and ceiling of a 250 sq ft room with a damp rag just seems like a PIA. Is there a better way?
Update: Well, I got antsy while waiting for answers (hey, it's a Sunday and people have better things to do than lurk SE), so I took matters into my own hands and picked up a mop with a wringable, rectangular sponge head from the drug store. What I did was get it wet and wring it out to dampness. After taking it from the ceiling to the floor and stepping to the side a bit to repeat, I'd be able to get about three sweeps of the wall before the head looked like it needed to be wrung out again. I did all walls and ceiling of my 250 SF room in well under an hour. There is now only ever so slight of a trace of dust on the surfaces. It may be ready to prime right now, but, since it was so easy, I'll probably do it once more tomorrow for good measure. It will go even quicker this time since there will be far less wringing out of the sponge head. If I don't get any other answers from anyone else that appear to be more practical than the solution I went with, I'll just answer my own question.