I did a lot of rust remediation in the early posts - the key thing to remember is that RUST EATS METAL. I can remove rust, in a variety of ways, but can't put the missing metal back. So not a big deal if it is some light, surface rust on the drive links or tie straps, but if the rivets are weakened . . . .Also can you rescue very rusty chains ie hanging on an outside garage wall?
OK for a rare chain that you want to display (e.g. see Post #133 - 140). OK for light surface rust. But if the chain is heavily rusted, seized, or has the chrome plating pitted, I would not run that chain.
Philbert