Is this considered used even though it's attached to the back of this cover and should it be removed......go ahead and laugh if you feel it's another stupid question
re: Question Regarding German Souvenir Sheet Scott #804
it should NOT be removed. it demonstrates proper international registration and is worth far more, if only because the number of potential bidders is trebled, than as a stamp.
if you must remove it, because you want the stamp, let me know and i'll trade you one of my off-paper copies
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"Save the USPS, buy stamps; save the hobby, use commemoratives"
re: Question Regarding German Souvenir Sheet Scott #804
Guess I will add my voice to that of the other members of this distinguished chorus.
I think what is particularly neat about the sheet/cover is the US registered mail cancel and the station cancel on the sheet which ad charm to the cover. If the sheet was not on the cover, the cancels would look weird and out of place.