I took a class on it; at least for me, it was pretty tough to get all the dust out, we eventaully left a couple in. After you clean it and take a test shot, chances are you've introduced "new" dust" lol. Also those swabs are expensive
It's also easy to 'streak' the sensor with the cleaning material. You also have to clean it quickly or again, more dust lol.
what we used was swabs (about $40) and a cleaning material (about $8)
The guy recommended it be done every month or so to avoid "stubborn" spots that wont' come off (like me, I had 3 of those that we gave up on).