A tide stain pen and applying detergent directly on to the clothing and wash as normal. If you have a dried up stain then you will need to soak overnight in order to remove the stain.
I have used rubbing alcohol to remove ink, dry erase is alot thinner, depending on the fabric, and "bleeding" you may also try saturating with hairspray, letting dry and washing.
Try rubbing alcohol. If that doesn't work use murphy's oil soap and then wash with dishwashing detergent. Make sure the stain is completely out before drying.