We are getting rid of our form-letter thank-you for donors and making a card with a "moving image" (someone in our program at work) on the front. Our volunteer designer suggested making it a postcard to save money. We'd love to save money on printing -- I'm just wondering if it's okay to have donation details (amount and org) sent to a donor on a postcard, or if I should keep it a mail piece in an envelope so that they are the only ones opening it (in case they don't want their postperson/roommate to see it). Is there a rule on this? Thanks!
