Many of our invitation clients ask about hand canceling stamps. No doubt you're heard about it, but may not be sure what it is. After all the time designing, printing and assembling your wedding invitations, you may be reluctant to hand them over to the post office to do what they will with them. Most pieces that you receive in the mail have been machine sorted and cancelled. They get a few things printed on them: a barcode, which could be on a sticker if your envelopes are dark, and the canceling mark, which "cancels" the postage, so that it cannot be reused. Sometimes, there will be a message printed on the envelope as well, like Happy Holidays.
To hand-cancel, you may have more luck to go to a small or suburban post office during a quiet time of the day. The hand canceling is a more precise, pretty looking postmark that must cover all of your stamps. hand-canceling prevents the machines from being placed in the automatic sorters, so it is ideal for envelopes that include a wax seal, or other bulky inserts, and generally, it's a much prettier look.
Our client took her lovely vintage-stamped save the dates to a downtown Chicago post office to hand-cancel, with great luck!