[Scoundreller]

I’m visiting some family and I’m a hero for fixing a couple devices that stopped working from alkaline batteries by using a bit of foil paper to overcome the corroded contacts.

Maybe not great in the long run (steel and aluminum don’t like eachother)… maybe I should have put on some grease…

[sowbug]

I swab the corroded contacts with white vinegar from the kitchen. It turns the white gunk into a foamy blob, and I assume it etches off enough of the corrosion to restore conductivity. I wipe the foamy part with the dry side of the cotton swab, and the device usually works again.

I started doing this as a kid, reasoning that the white gunk looked like baking soda, which is fun to combine with vinegar, so let's see what happens. I just looked it up, and it appears that the process is legitimate and safe. The vinegar turns potassium carbonate into potassium acetate, also producing carbon dioxide.

[bluGill]

That is step one. However that is rarely enough: the corrosion eats through the chrome plating on the steel (chrome is a good conductor, steel makes a great spring), and that rusty steel is a poor conductor. Even if you polish the steel, it will rust again soon. (chrome plating requires nasty chemicals, not something to attempt at home - I suspect you could silver plate at home for cheap enough but I haven't tried it)

[IAmBroom]

Pish, what's the worst that could happen when rusted steel and aluminum are kept in a sparky environment?

[Dylan16807]

In chunks like that, with such little metal total? Nothing. Even if you sabotaged it to heat indefinitely the plastic around it would burn and leave the aluminum unreacted.