Luck chain letter.  Luck By Mail type (earliest). "The luck of cards have been sent to you."  "You will receive it by mail".  US, 1949.

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United Western Airlines Treasure
The luck of cards have been sent to you. It has gone around the world four times. The one who breaks the chain will have bad luck. Please copy and see what happens four days after receiving it.
You are to receive good luck four days after receiving it. It's no joke. You will receive it by mail.
Good luck!

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Published: El Paso Herald-Post, 21 Nov. 1949, p. 1. "'Good Luck' Chain Letters Circulate Here". "El Pasoans are again receiving anonymous chain letters." Entered by DWV, Dec. 2, 2013

le1949-11-21p1_bym!_ByMail_q5d24w4

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