First, I will paint the framework if it shows any corrosion, naval jelly the rust spots and paint according to those instructions, as needed.
Then I just smear a thin layer of axle grease on the metal with a paper towel, or my fingers.
Once the batteries are in, I use some sort of de-oxidizer grease on, and over, the connections.
That usually works for me, it just attracts dust, and maybe a bit dirty next battery removal.
At least the metal part has kept its integrity.
This is just how I tackle it.
Kind of old school!
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