I actually asked this at my post office last year, as I wanted to decorate the envelope with used stamps as a birthday theme. The answer was:
For used US or foreign stamps, you should not put used stamps on the front; it might be confusing to see something with a partial strike/cancel where they would expect a full cancel tying it to the cover.
For non-US stamps, you can put mint stamps anywhere but the upper right section where postage usually goes. But the clerk recommended putting these on the back too.
FYI, I had sent a decorated envelope to someone with CTO and mint stamps on the front and back; the ones on the front arrived partly peeled off. All of them. The ones on the back were fine.
Peter
I have had no problem placing unused foreign stamps on the left side of envelopes. You just have to make sure that the stamps do not portend to pay for the postage of what you are mailing. When sending off envelopes/parcels like that, I always take them to the post office to have them hand canceled. The clerks like to see the stamps as well, and who knows, you may inspire a clerk to start collecting stamps (I have with two clerks), or resume a dormant collection.
Please... let me explain before you try to shred me.
If one wishes to send a letter using current, new, and correct postage amount, would adding an "old" and "previously cancelled" stamp to the envelope be an issue.(as the "cancelled stamp really just for looks) Or would the USPS simply toss it back, not paying attention to the "correct" postage?
re: Can Used stamps still be used on postal letters?
I actually asked this at my post office last year, as I wanted to decorate the envelope with used stamps as a birthday theme. The answer was:
For used US or foreign stamps, you should not put used stamps on the front; it might be confusing to see something with a partial strike/cancel where they would expect a full cancel tying it to the cover.
For non-US stamps, you can put mint stamps anywhere but the upper right section where postage usually goes. But the clerk recommended putting these on the back too.
FYI, I had sent a decorated envelope to someone with CTO and mint stamps on the front and back; the ones on the front arrived partly peeled off. All of them. The ones on the back were fine.
Peter
re: Can Used stamps still be used on postal letters?
I have had no problem placing unused foreign stamps on the left side of envelopes. You just have to make sure that the stamps do not portend to pay for the postage of what you are mailing. When sending off envelopes/parcels like that, I always take them to the post office to have them hand canceled. The clerks like to see the stamps as well, and who knows, you may inspire a clerk to start collecting stamps (I have with two clerks), or resume a dormant collection.