Hi TN56,
If you are finding nice new notes (zero imperfections, scratches, or roller marks) in ATMs, look for radars and special serial numbers. Maybe keep a couple of each prefix to form a set.
The prefix INS is a bit special because it is a "change-over" prefix. That is when the signatures printed on the note change at some point in the numbering. INS started with Lane/Macklem until about serial number 3969000, and then changes to the signature combination of Rogers/Macklem. INS is the first prefix within the $5 denomination that bears Carolyn Roger's signature making those notes special. The more perfect they are, the more valuable they are.
Hope this helps,
Cheers,
Breanna