My old school ID left ink imprints on the ID slot in my wallet. Any ideas on how to clean the clear plastic?

It was a really crappy old highschool ID card that i left in there for like 3 months and just took out. I guess the heat made the ink come off the cheap plastic and onto my wallet's ID window. Im trying to think of a way to clean the inside of the plasic window without damaging my wallet. I really like my wallet.