There's vintage jewelry and then there's vintage designer jewelry. Sure, there's value in your old man's gold accessories, but there's nothing like a quality chain from one of your favorite luxury brands. Of course you have your go-to Chanel and Versace jewelry, but keep in mind that's not all that's out there.
Christian Lacroix made dope chains back in the day, and so did Givenchy. Both Hermès and Cartier came out with some pretty nice watches, too.