Occasionally, cracks can develop in the corner of a wall because of corner bead coming loose or due to settling of the wall. Corner cracks can be filled in very simply with joint compound. Always repair the cause of the corner cracking if possible to prevent the corner from developing more cracks. You can maintain the look of the corners in your home with a few shop tools and save yourself time and money.
Remove any loose pieces of drywall or plaster from the corner by hand, and smooth it out with a piece of fine-grade sandpaper.
Secure any loose corner bead with screws and a drill, fastening the corner bead to the wall framing.
Fill in the cracks with joint compound, using a putty knife to apply the compound, and allow it to dry.
Sand the joint compound with a fine-grit sandpaper so the filler is smooth on the wall.