Dip a cotton ball or swab in rubbing alcohol and go over the scuffed area of the leather. This may be enough to remove the scuff, depending on the scuff's size and how deep it is. If the leather item you are repairing contains non-leather features, such as belt buckles or shoe heels, cover them with masking tape before you begin cleaning.
Apply a small amount of toothpaste to the scuff and rub the area with a soft, clean cloth. Use white toothpaste, rather than gel toothpaste, to remove the scuff mark.
Use a refinishing spray across the scuffed area. Apply the spray lightly and evenly and allow the spray to dry. Apply a second coat or more if needed until the color and texture of the leather are even. Allow each coat to dry, then remove the masking tape.