My U.S. Flag 'Forever' stamps say 'Forever.'
Why it is a pun to put 'Forever' on an Emancipation Proclamation 'Forever' stamp?
The famous phrase freeing the slaves in rebel territories is "then, thenceforward, and forever free."
So here we have the "forever" of the now-familiar "forever stamps" completing the idea "free forever."
Maybe you had to be there ... or have taken a lot of useless lit classes.
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Anyway, here is the last commemorative stamp:
Have 50 years really gone by since?
You could mail a first class letter with one of these.
Check out the price.