Blot as much of the stain as possible with paper towels if the spill is fresh. Do not rub, since this can help the stain to spread further. If the spill is older, start with the next step.
Sprinkle talc powder onto the stain and allow it to sit overnight. Dark spots are usually a result of an oily stain. The talc draws the stain from the leather safely without rubbing.
Brush the talc powder away and check to see if the stain is removed. If the stain is just as deep as it was, pour more talc powder onto the stained area and allow it to stand overnight.
Apply a small amount of leather cleaning solution onto a microfiber cloth.
Gently rub the leather cleaner across the stain, moving from the outside toward the center.
Buff the area with a clean microfiber cloth to dry the leather.