Whether you have ink on a window or glass coffee table, you are left in a situation where you must find an ink removal routine that is harmless to the glass. Ink is a hard substance to remove, so you want to use an effective solution that immediately breaks apart the ink residue. Another key is to find a cleaning element that dries clear, as you do not want a film left behind on the glass from your cleaning solution.
Mist glass cleaning spray over the ink, then wipe it off with a paper towel. This typically removes light ink marks from a writing pen or similar object.
Pour rubbing alcohol or hairspray over a paper towel until it is moist. The hairspray has less of an alcohol content so it may take a bit more work than going straight to the alcohol. Substitute the hairspray when you have no rubbing alcohol on hand.
Place the paper towel over the ink stain and let it sit for about 10 seconds.
Use the paper towel to scrub off the ink. Apply pressure as needed, and use a fresh paper towel if necessary to remove the remainder of the ink.
Dry the area with a clean paper towel. The rubbing alcohol dries clear and free of residue.