So at the beginning of summer I repurposed an old Android phone into a dedicated emulator. The phone's old enough it has an honest to god user replaceable battery so I decided to get another one and keep it in my backpack to double my gaming time.

A few weeks later I got caught in a thunderstorm and got absolutely drenched head to toe. I got home and found the phone and bluetooth controller were just a bit damp but okay, but I completely forgot the spare battery until the next day when I discovered it still in my backpack and absolutely soaked. I dried it and left it to dry on a shelf, and noticed some bluish corrosion forming at the contacts the next day that I promptly scrubbed off. I noticed more corrosion a few more times in the following days, but it's now sat on that shelf since June and looks normal.

How bad of an idea would it be to put it in the phone and see if it still works or holds a charge?