I really like the goal behind this project. Once you start sorting hardware into usable categories, you realize how much perfectly good material gets thrown away simply because it's rusty or mixed together.
From what I've seen during garage and workshop cleanouts, organization usually creates more value than trying to restore every single piece. If a batch is only lightly rusted, electrolysis seems like one of the better options because it removes rust without being too aggressive on the metal. For heavily corroded pieces, I usually find it's more practical to recycle them and keep the hardware that's still structurally sound.
One thing that has also helped is separating bolts, nuts, washers, brackets, and specialty fasteners before cleaning. Working with similar items in batches makes the whole process much more efficient than cleaning everything together.
I also came across a garage cleanout guide that emphasizes sorting reusable items before deciding what should be recycled or discarded, which follows a very similar approach to what you're describing.
I'd be interested to hear an update once you've tried one of the bulk methods. It would be great to know which one gave you the best balance between cleaning time and preserving the hardware.