Write an article based on this "Blot excess ink immediately. Try isopropyl rubbing alcohol. Consider using vinegar on the ink stain. Try hairspray. Try a commercial stain remover. Rinse the area thoroughly with clean water. Repeat cleaning process if necessary."
You will have a harder task removing the stain once it sets in and drys. First focus on removing the excess ink using a dry towel or a paper towel to absorb the excess liquid.  Blot the ink spill gently, putting a little to no pressure on the area. Try to remove as much ink as you can working from the outside towards the center. This will prevent the stain from spreading. Don't rub or scrub the area, which can spread the stain and work it into the fibers more deeply. Instead, blot gently to get as much of the ink out as possible before you clean it more deeply. Ink stains often come out with rubbing alcohol, regardless of the style of upholstery in the car. 90% isopropyl alcohol is preferable, but you can use 70% if that's the only variety available.  First, test the alcohol in an inconspicuous place of the car upholstery to make sure that it won't damage the upholstery material. Apply rubbing alcohol on a clean white cloth. Do not pour alcohol directly on the stain. Dab the ink stain with the cloth carefully and gently. Do not rub or wipe. Rubbing will cause the stain to spread. Repeat the process again until the cloth is not absorbing any more of the ink. Make sure to change the cloth when it is saturated with ink. Don't use alcohol on acetate, rayon, or triacetate. These fabrics will stain and leave bleach-like spots if treated with alcohol. Its acidic properties make it remove stains effectively. Plus, it's safe to use, gentle on hands and environment friendly.  Combine 1 tablespoon of dish washing soap and 2 teaspoons of white vinegar in a cup of water. Dab the solution on the stained area using a soft cloth and rub the area gently. Let it sit for about 10 minutes and then wipe it with cold water using a soft cloth. Rinse the affected area thoroughly. Repeat until the solution is gone. Not just for hair anymore. Hairspray is a strong and somewhat volatile solvent that can be an effective ink remover, used in small doses on both cloth and leather. As soon as you see the stain, spray a little of the hairspray over the top and quickly wipe away gently, using a clean, dry cloth. Repeat the process until the ink has gone. Some people report that stronger hairspray has better stain removing properties, though it's difficult to verify. Try whatever hairspray you've got on hand and use in conjunction with other cleaning solutions, if necessary. If you want to make a run to the store to get up the stain, many cleaning products are available which should gently help to lift the stain out of the fabric and leave your upholstery looking clean. If you don't want to use a home remedy, try any of the following products:  Oxi-Clean Kaboom Dry-cleaning solvent Motsenbocker's Liftoff After using a cleaning product of your choice on the stained area, try to go back over it with clean water. Wet your cloth with water and re-blot the area thoroughly with water, dampening it gently if possible. Do a few rinsing passes with your cloth to get as much of it out as possible. Extract the water by putting a dry towel on the affected area. Use a clean towel and line it over the stained area, pushing down hard with your hands to absorb the water. Let the area dry and re-examine the stain in a few hours. If there's still a significant amount affected, repeat the steps above, trying another cleaning product if necessary. It usually will take several attempts to get a stain out completely, so don't get frustrated. Be persistent and try again if you don't get the stain out the very first time.