Sit Ubu sit! LOL - The answer to your question totally depends on the type of ink involved and whatever the cover is on the LCD, glass, membrane etc etc. My suggestion would be is if this is like a marker type pen, to look up the manufacturer and ask them. Pen inks these days are made up of so many different things. Let us know what you are able to ascertain. Hope you can get things cleared up.

OK, I talked to a IT person at work and they told me to try WD-40 and a Q-Tip.  Well for the most part it's gone.  

FYI, WD40 is also great for removing crayon from walls, furniture, etc.! Also takes off stickers (when they get older). Only thing it doesn't do is lubricate. (NEVER use it in place of oil!)