Outside corners sit exactly where vacuum heads, shoes and moving boxes pass. The repair needs to reproduce both faces and the crisp change in direction. Filling the crater is only half the job; the corner still has to look like the same moulding when viewed down the hall.
Check whether the corner is chipped or crushed
Look at the exposed material and the joint behind it. Solid wood may have lost a small splinter, while MDF can have a broader compressed or furry area. A sound chip has firm edges around it. If the board moves, the mitre opens when touched or the lower edge is swollen, resolve those conditions before applying a cosmetic repair.
Keep a loose matching splinter if it is intact, but do not assume gluing it back will be durable when the surrounding fibres are broken. If water was involved, compare the swollen MDF checks. A filler patch is not a way to restore softened core material.
Small chip, sound corner
A compatible repair can rebuild a limited defect while retaining the original moulding.
Crushed or missing profile
A matched replacement section can produce a cleaner and more durable corner.
Joint moves
Stabilise the trim and resolve the joint before making either cosmetic repair.
Use the undamaged profile as your reference
Photograph the corner from both directions and compare an intact section. A short profile offcut can help check the shape as the repair is formed. Protect the floor and wall from the chosen product. Avoid smearing a wide area; the larger the patch, the more finishing you have to blend.
Minwax's filler directions distinguish small repairs from holes needing another product and require drying before finishing. Choose a product for the actual substrate and repair size; do not turn those directions into a universal recipe for a large unsupported corner. Follow its shaping, drying and coating instructions.
Match the thickness as well as the pattern
When replacing moulding, take a sample or a clear end profile to the supplier. Two boards with similar top curves can differ enough in thickness to create a visible step. Decide whether a whole short run to the next corner will look better than a conspicuous inserted patch. Preserve the wall finish and adjoining flooring during removal.
Unknown old paint needs assessment before sanding or cutting through it. Health Canada's renovation guidance explains the lead-paint concern. Once the coating and work method are appropriate, establish the fastening locations rather than driving nails blindly near services or the floor edge.
Check it from normal walking height
After levelling the repair, inspect both faces under side light. Prime and repaint to a natural break using a compatible system. A corner that looks perfect from a kneeling position can still have a rounded bulge visible down the hall. For tiny surface hollows after painting, use the nail-hole finishing checks.
If the same corner is hit repeatedly, change the cause where possible: furniture clearance, a door stop or the cleaning route. A protective detail can be considered for a high-impact location, but agree on its appearance first. Rebuilding the same sharp edge every few months is a sign that the daily use needs attention.