A rusty corner bead or a rusty angle bead can be a real problem to fix and must be done correctly because if you try to paint or paper over it without fixing the rusty bead first the rust will eventually come through the paint or paper. This video shows how to remove the plaster for the affected area, clean the bead and apply some rust convertor before filling the area and painting it using a stain blocking primer. Once the primer has dried you can paint the damage with the paint of your choice, or even wallpaper over it.