Here are two return fingers.
First is from 1997 on the US postcard UX220: the hand is marked "Returned to Sender" and in line below is "Forwarding Order Expired // Media PA 19063-9997" The hand and text are so well-aligned I suspect they formed a single rubber stamp.
The sender was Clarence D. Bell, (1914-2002) who served as a Republican state senator from 1960 until his death in 2002, which apparently makes him the longest serving state senator in Pennsylvania history.
Next is one of the sad ones.
It was sent September 18 1945 from Big Spring Texas by Air Cadet Albert LeBreton to a Flight Officer Leon C. Kirk based in North Carolina. The Air Cadet free franked it. The impression of immediate interest is the return finger marked "Returned to Writer // Not Found" which are a single stamp. There is also a second stamp reading "Return to Sender // No Record at // Seymour Johnson Field // North Carolina." The Goldsboro PO mark on the verso for the return is September 27th.
As you can see, on the front there's a manuscript note "Deceased" signed and dated Sept. 24th 1945. I looked up Mr. Kirk and found he was killed at age 20 while on a routine training flight out of Goldsboro when his P-47 collided mid-air with another over Richmond, Virginia on Sept. 1. This is, of course, two weeks after the Japanese had announced their surrender and coincides with the day of the official ceremony on the USS Missouri (Sept. 2 in Japan, and Sept 1 in the US).
Air Cadet LeBreton's enclosure to Kirk was an announcement of his graduation from Advanced Bombardier School at Big Spring.