Many believe power-sanding cures a world of ills, and it can. But it also can cause its own set of tool-mark problems. Take care here or you'll risk the hard work you spent building the project.First, wipe down all the surfaces you plan to sand with a tack rag to remove sawdust and other debris that can make scratches when they are picked up by the sander. Then, move up through the sandpaper grits in small steps from coarse to fine and let the sander do the work, wiping down the piece between each grit change.Next, use a soft cloth to apply mineral spirits to all the areas you sanded. The "mineral spirits rubdown," shown left, offers three benefits—it gives you an idea what the wood will look like under a clear finish, shows up glue stains you may have missed, and highlights any remaining tool marks, including notoriously hard-to-see sanding swirls. Note the spots that need more work and go back to them after the mineral spirits dries. This trick also can be used prior to assembly or during dry-fitting to find problems that would be difficult to repair after assembly.