I have added a new breakfast room off of my kitchen which has new drywall and mud. I want to begin the process of painting the walls, but have noticed that the drywall is covered in fine dust from sanding the new mud spots. Is it ok to wash the drywall down with a damp rag, or should I be using a dry tack (spelling?) cloth to pick up most of the dust. I want to make sure the walls are clean before beginning the priming process.