Depends on the surface whether you can remove it. If the Sharpie has been used to write on paper, you are out of luck. But on a non-porous surface like plastic, white board, glass or sealed wood, just write over the Sharpie ink with a dry-erase marker. Let it dry completely and wipe off with a cloth or tissue. Usually works for me. Good luck. Inside a book you might just simply cover the entire area with adhesive-backed paper, hopefully not see through. Could also spray with photo adhesive and cover with opaque paper. All the best with this problem. and with MIL!