Pull the nails out of the old desk around the edges of the leather using a nail puller.
Gently clean the area where the leather was attached to the desk with steel wool, removing any grime or dirt on the desk top.
Measure and cut the leather using a fabric tape measure and scissors.
Stretch the leather over the antique desk where the old leather was situated and fasten it to the desk with upholstery nails using a hammer. Do not glue light or thin leather to the desk as the adhesive will seep through and may stain the leather.
Insert a putty knife under one corner of the leather and begin to pry it up of the desk. Scrape away glue as you pull the old leather off using the putty knife.
Abrade the desk where the old leather covered it using medium-grade sandpaper, then wipe down with a tack cloth to take up the dust.
Measure and cut new leather using a fabric tape measure and scissors.
Fit the new leather over the desk, making sure it is the right size.
Turn the leather over, exposing the underside. Dot the underside of the leather with upholstery adhesive, then carefully turn it over, stretching the leather over the antique desk. Smooth the leather out with the palms of your hands, flattening out any creases.
Let the adhesive dry for 12 hours before using the antique desk.