Cleaning battery contacts

[sylvandb]

I remove the majority of the deposits by scraping and blowing. Try to not let pieces fall into the calculator, and do not get them in your eyes.

Alkaline batteries are alkaline, so I use household vinegar on a cotton swab to dissolve and neutralize what is left.

If the deposits do not react (a bit of fizz and bubble) in vinegar, perhaps they were simple carbon-zinc cells. Those are acidic and a saturated baking soda in hot water solution could be used to neutralize those deposits.

Usually the nickel plating on the contacts will be gone but they will function OK. If you have the contacts out then you could use some solder (lead-free if you like) to tin the contacts. This requires substantial heat and beware it could easily melt plastic or desolder the contacts from the board.

Usually I'll coat the contacts with petroleum jelly (e.g. Vaseline) to prevent further oxidation.