[Michael B]

The cachet is the design on the left of the envelope. These have been done since the 1920's by a variety of companies (Crosby, Artcraft) and can be quite elaborate as the Artcraft engraved ones or as simple as the one shown here. They were mainly done for first day ceremonies when the stamp was issued, launching of ships (ship covers) or special events like the Olympics. The US Postal Service has nothing to do with the cachets. They have control over the stamps and cancellations. As long as an item has proper postage they will affix a cancellation. The item does not need to be addressed nor does it need to be mailed. You can also get multiple cancellations on an item as long as new and proper postage is attached. The postal service cannot affix a cancellation to a stamp that has already been cancelled. It must be an unused stamp with the current postage. For signed covers, such as the one shown, it is more desirable that it not be addressed, U/A is the designation on listings of covers being sold on ebay. Covers that are U/A look more attractive as there is a larger space for someone to sign. They do not have to squeeze their signature in another spot. On this cover signed by your grandfather it is too bad that he did not use the same pen to sign his name as he did to write in the years. Sharpie can spread so bad on porous paper that the letters merge into each other and he seems to have had a very nice signature.