To remove a larger, stronger ink stain or an ink stain on a delicate piece of clothing, you're going to want to start by running the item under cold water.
Try rubbing the fabric against itself to get some of the ink out. Then fill a bucket with hot water and mix in liquid laundry detergent and a splash of ammonia. Dip the clothing in the mixture and rub the stain with your hands and against the fabric, rubbing ink out.
Once you're done, let the item soak in the bucket for approximately an hour. You can vary the time depending on the size of the splotch. Check on it and stir and rub the stain as often as needed.
When the stain is faded or gone completely, rinse the clothing under cold water, rub in a little more liquid detergent, and throw it in the wash. After you let it air-dry, the stain should be gone.
