(I was working something similar to this at work so I tacked a little on to my questions to M&P)

Almost all SS is cleaned with acid at some point. When they make SS parts they make certain they get all the acid off (at least for high quality parts) This can get complicated like rinse - soak - rinse - .... while monitoring the pH to make certain there is no acid left. It is one thing to clean a flat plate. Cleaning a SS cable is entirely different. Acid wicks into cracks and between strands at 100% concentration and it has to diffuse out. A slow process involving many water changes.

Rust converters are acids. They have a tendency to get trapped between the strands and more importantly wick into surface imperfections and micro cracks. This can start a real corrosion problem that leads to failure, not just surface rust.

If you are going to use a rust converter, you must be certain you get all of the acid off. Rinsing with a garden hose will not cut it. The acid will have to diffuse out. That means soaking, brushing, and rinsing and repeating.

I don't use acid based cleaners on structural components. I never even considered it because it seemed like a dumb idea. Now it seems like an even dumber idea. However I might give my competitors a bottle for Christmas.