So, you asked about rust. I'm going to toss this out there for you before you hit the OA bath thing. It's definitely easier to spot-treat, it's e-friendly, and super easy to use, just soak paper towels and wrap around the metal. Let sit, then rinse off with clean water, wipe down. https://www.evaporust.com/

You can buy it on Amazon, I had trouble finding locally. A little bit goes a long way if you're doing the paper-towel wrap method.

I didn't believe the hype, but for $8 to get a bottle enough to do 50 bikes, I figured "what the hell?" and bought it. I won't screw around with other methods. This stuff is great for cranksets and frames. I reckon if you wanted to buy by the gallon, you could soak parts in it, then pour the remainder back in the jug as long as you removed any loose material off the part before hand.