Leather is virtually maintenance-free as a furniture covering, but ink from a ballpoint pen can be particularly hard to remove. Ink marks are certainly easier to remove than a rip, however. Follow these steps to remove those pesky stains various upholstery.
Work on removing the stain as soon as you discover it. Dried ink is especially difficult to get out, unless you act quickly.
Blot the stain with a soft dry cloth or cotton ball.
Moisten another cloth and clean lightly with circular movements. Dry the surface with a soft cloth.
Try a little saddle soap or another leather cleaner, but first read the label regarding its safety for use on your particular kind of leather. You may also try removing the stain with lukewarm water and shampoo.
Contact the manufacturer for a remedy for the type of ink used - the company may sell its own solvent.
Traditional wisdom recommends treating ink stains with milk or tomato. Cover the stain with a little milk or rub it with the cut side of a half a tomato. Take more care with the tomato remedy, as tomatoes contain some acidity. Rinse either treatment well.
Avoid any kind of cleaner or detergent, unless it's specified for the particular sofa or particular leather, as it could harm the leather.