HP-25C It’s alive!

[Wilsom]

The corrosion of battery connectors in Woodstock calculators is an unavoidable issue due to HP's choice of using silver as the contact material, unlike the more common nickel or gold plating found in other calculators, including HP's own other series. As most of us have experienced with silver items, it tends to oxidize when exposed to moist air, despite efforts to prevent it.