Do any certificates retain values as securities?
Yes, a few do.
A few antique bonds still hold value as securities, even though they are no longer traded on stock exchanges. I do NOT have the expertise to estimate the values of such certificates.
You are free to research your certificates on your own, but it will be challenging. If thinking about doing your own research, check out the advice on a dedicated page on Investopedia.
Yes, I'm a research guy, but researching security values is an endeavor where I leave the work to the pros. Here are the companies in North America that actively research the values of old securities on a fee basis.
Before contacting any of these services, re-check your certificates carefully. Are they cancelled in any way? If they are cancelled, no matter how lightly, they have no value as securities. (See Cancellations for more insight.) Moreover, just because certificates are not clearly cancelled does NOT necessarily mean they retain value as securities. Approach this process with your eyes wide open.
Uncancelled gold bonds
I reserve my strongest possible warning about buying and selling uncancelled gold bonds as investments. Please be warned that...
GOLD BONDS CANNOT BE REDEEMED FOR GOLD !
NO WAY ! NOT EVER !
U.S. laws (see Gold Bonds) outlaw redemption in gold. If you encounter anyone offering to sell gold bonds as investments, STOP! Contact an assistant U.S. attorney immediately! The Justice Department and Treasury Department would like to talk with them.
Gold bond scams are nothing to mess around with.
Want to believe in fairy tales? Go right ahead. Just don't say I didn't warn you.
Be aware that a number of U.S. citizens lost substantial money on gold bond schemes in the late 1990s. I received several similar reports around 2015, but I haven't heard of any in the last few years. Please visit the U.S. Treasury Department's website for in-depth information and what to watch out for. That site also has links to other sites that describe similar non-U.S. and European schemes.