Yikes! I don't think Goof Off would work, may take the finish off the leather and leave it looking dull. I know DW40 gets pen off but again, I think it would ruin the leather. The only thing I can think of is using the Magic Sponge on it maybe??? I use the MS on everything and I would say about 95% of the time it gets whatever it is out. Or rub a leather cleaner into it and see if that works.