New Drywall and Wallboard: Tape joints should be sanded smooth and even with the drywall or wallboard. Using a damp cloth or sponge, wipe tape joints and all wallboard surfaces to remove all sanding dust. Be sure to remove all chalky residue before priming. Allow to dry, then prime. For previously painted surfaces remove all dirt, dust, grease and oils by using a non-residue cleaner to clean the surface. Scrape off any loose, cracked or peeling paint. Patch cracks and nail holes. Sand smooth, then spot prime.