Another interesting thread - thanks for starting it Robert!
Quote:
How boring that would be if every one of us all collected mint stamps only.
I agree! I simply love postmarks - a clean mint stamp collection without any postmarks whatsoever - no sign of the postal service stamps were supposed to do, no evidence of where or when a stamp was used....well, then one could maybe just as well collect stickers ....

I was not aware that the digit on top of the squared circles represent the clerk # - cool!
Rene - lovely covers! Afraid neither of them are squared circles, but guess you know that already (?) The first has a numeral cancel in duplex (duplex with CDS on a single hammer), 2nd has a mute 9-bar cancel in duplex and the last has a lovely 'fancy' cancel and CDS.
btw - quite a peculiar shade on the 3c small queen on your first cover - seems to have oxidized into a purple shade! (at least on my monitor)
Keep them coming
