...does anyone know a way to erase a permanent marker - in this case off of a slot card?

I picked this one up in a local casino this week, didn't have my own card with me so they gave me this blank card to use just as a cash card - they are used to track play, and also slot machine credit - you take the card to the cash desk when you finish to get your cash. Needless to say I didn't have any cash to take out at the end ( ) and so the card just stayed in my pocket, and I'm wondering if it could be cleaned up. '500' has also been written on the white strip on the back.

Any advice gratefull received!