Absolutely follow Thom's advise. In my case, there was a bit of a learning curve in that, at first, I was so petrified of destroying my camera, I only used minimal pressure which led to minimal results. Gradually, I got confidence and began to get most of the dust. But there came a point when I realized that (for me) the sensor swabs I bought were not doing a thorough enough job, which is when I made my own swab. Your advise about proceeding carefully is appropo.