Papaw,
I've had good luck using Evap-O-Rust that has been stored for years, both new and previously used. I have always filtered the used EOR before returning it to the container.
I also go to some lengths to remove contaminants (i.e. grease, oil, dirt, and loose rust or chrome) from any tool that headed for an EOR bath.
You can always run a small test with a small rusty item and a small amount of EOR. You have nothing to loose.