How to Work in Corners?

Apply less material in the corners and work carefully with smaller tools. The cleanest method is to finish the corner in stages: first one wall, then after drying, the second wall. This applies to both internal and external corners. A thick build-up on the edge is a common cause of cracks, bumps and poor sanding. It is effective to work the corner gradually, meaning first one wall and after it has dried, work the second wall. This applies to both internal and external corners. It is not advisable to leave a large amount of material on the edge. Work carefully.