Selling Nostalgia T-shirts: When do you need permission?

Dear Rich: I'm a graphic designer and lover of old nostalgic items. I would like to scan in and "clean up" art from items such as luggage stickers, water decals and pinback buttons, to reproduce on t-shirts and other things with intent to sell. Most of the items date anywhere from the 1930's up to the 1960's and have little or no ownership or copyright info on them. Am I going to run into problems doing this? I'm enclosing some examples. The short answer is nay problemo! The Dear Rich Staff is pretty sure you're not going to run into a problem. However, because there's nothing quite as satisfying as hearing our own voices (over and over and over), we shall note some of the applicable rules of copyright and trademark law 

Time is on your side. Chances are slim that you will run into a copyright issue if the work is pre-1964 since that would have had to have been renewed at the Copyright Office (and it's very unlikely that luggage stickers and buttons would have been renewed). So most, if not all of your material is public domain. As for trademark law, none of the examples furnished seem like they would trigger a trademark claim but if any of them do refer to current companies, or to products or services now being sold or offered, a conservative approach would be to avoid them. P.S. To learn more about the public domain, see Stephen Fishman's book The Public Domain: How to Find & Use Copyright-Free Writings, Music, Art & More (Insert FTC disclaimer here).