Surface scratches only affect the topmost layer of the leather. You may see some discoloration, but the scratch does not feel rough to the touch. To repair this type of scratch, use a leather repair pen that matches the color of the furniture. Fill in the scratch marks with the pen.
Punctures can be caused by cats when they exercise their claws on the furniture as they would on a scratching post. To begin a repair on this type of damage, use a pair of regular scissors to cut any small pieces of leather coming out from the furniture. Use repair putty to plug the holes and let it dry overnight. Color over the putty with a leather repair pen if there is a significant difference between the puttied area and the regular color of the sofa.
If you have deep scratches, the process is similar to repairing puncture marks. However, when applying the repair putty, make sure you spread it very evenly along the scratches so the resulting patch dries evenly. If any part of the scratch breaks the fabric so the inside of the sofa is exposed, you need to enlist the help of a professional to repair the surface.
Since leather putty and leather repair pens contain harsh chemicals, it is important you keep pets and small children away from the couch. Take care not to get any of the repair materials on your clothes or on carpeting, as the materials permanently stain. If possible, keep the sofa in an unused room or garage until all the repair materials have dried.