I'm moving to a new house and I'm going to attack this problem holistically (sp?). I really hate dust. I think if you don't want dust on your contact print you should focus on keeping it out of your house first. That means, making sure you have a clean furnace filter, keeping your house at the proper humidity, getting your ducts very clean on a regular basis. Keeping your house vacuumed and dusted regularly. And keeping an air clener/purifier running locally in your darkroom. Then, running through your darkroom with a slightly damp rag prior to your session and finally keeping an anti-static brush (I use the same kind to clean my records) and a can of compressed air handy should do the trick.