If there is no unclaimed property listed at the Illinois Treasurer’s office, I think you can write this off. I have no idea what a “retirement certificate” is — and I remember the S&L crisis in which Lyons failed. It was a headline financial disaster. I think at the time they were selling uninsured “certificates” which would have no value today! (except maybe as a collectors’ item!)
In fact, you might want to read this article I found!