Scrape off the old leather. Remove as much of the old glue as possible with the scraper without damaging the wood underneath. Spread glue stripper on the remaining glue and let it work as directed. This typically softens the glue in a few minutes so it can be removed. Remove the rest of the glue with clean rags.
Cut a new piece of leather that fits in the place of the old one. Measure around the leather piece and cut a length of trim to this measurement.
Thread a sewing machine with heavy-duty thread and fit it with a needle suitable for sewing leather. Stitch the trim to the leather piece’s outside edge. This gives the edges a finished look instead of leaving them raw.
Spread a thin layer of leather adhesive on the desk with a paintbrush. Coat the surface without having too much, which makes laying the leather difficult.
Lay the leather into position on the desk. Set the leather into the adhesive with your hands and work out any large air pockets. Following this with the brayer removes any remaining air and ensures a tight bond. Pay careful attention to the edges so that they won't lift up. Let the glue completely dry. Usually this takes 24 to 48 hours.