@ OP, your pics are not working.
Try uploading them here instead of using photobucket.
I've restored a few cars.
Just sanding and painting don't work well if there is any pitting.
Slows it don't. Doesn't stop it. Rust will grow back from the bottoms of the pits and bubble the paint
If there is pitting you either need to use one of those toothbrush style SS wire brushes to clean out the pits completely or go the chemical route.
The cheap red-neck chemical route is to use something like tobacco sauce + the SS wire brush.
It's very acidic and it works better than you'd think.
I use a brand called Valentina because it's potent, cheap and comes in a big bottle.
This won't stain you plastics (but it might give you clean spots).
The down side is the process is messy and you'll probably have to give your case a hot shower before you paint.
It's not a good choice is you have a large area to cleanup. Great for small spots.
Using a plastic (vs SS) toothbrush this works pretty good to derust the metal around d-sub ports or to clean slot contacts.
Even for that it's messy and the cleanup is more work than the job itself.
The middle chemical route is the automotive converters.
Some of those work very well but most will stain plastics black if you are not careful.
Seems you have plenty of guidance there.
The most effective and way more expensive method is to use a marine rust converter product called Ospho.
Been around since 1947 and I dunno if you can even get it outside the US.
It's tough to find inside the US. True Value Hardware (or was it Ace?) will order it for you in 1 gallon size.
Treating a whole case would probably only take a pint. A gallon will derust a lot of cases.
For this stuff you want to do a complete disassembly down to just metal. Big job.
You need gloves and eye protection for that one and following the directions is not optional.
It's a phosphoric acid based concoction that leaves a paintable surface. Don't use on Aluminum.
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Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
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