The cancellations listed in Linn's Postmark Pursuit column are authorized by the United States Postal Service for the periods indicated. Requests must be postmarked no later than 30 days after the date of cancellation to qualify for service.

Affix correct postage to an envelope or postcard of your choice and address it to yourself or someone else. Insert cardstock of postcard thickness in the envelope to protect against bending. Place it in a larger envelope addressed to the station name and to "Postmaster" of the listed city, including the post office address and full nine-digit ZIP code as indicated.

Your envelope or postcard will be returned to you through the mailstream. If you would like your items returned under protective cover, include a larger, addressed envelope franked with 49¢ postage, or an addressed large glassine franked with 21¢ postage. Include a note requesting that the canceled envelope be returned inside the envelope or glassine.

Requests for cancels with stamps and postal stationery not in nationwide release on the date shown in the postmark might not be honored.