The X10 RF Remote Control in the kitchen stopped working, which could mean only one thing: a set of dead AAA cells.
A negative terminal in the battery compartment showed the expected corrosion:
The corrosion evidently pushed the cell away from the terminal just enough to starve the remote.
The cells, on the other paw, looked just fine:
They’d been in there a year, sported a date code that’s still a few years in the future, and had a 1.3 V loaded output. Looks like that little bit of corrosion gave me enough of a heads-up to get the cells out before they rotted.
The Smell of Molten Projects in the Morning 
So what do you do about corroded terminals to get them working again without mangling them? I’ve tried fine sandpaper on the end of a stick but I’m hoping for something more sophisticated. I have these visions of you electro-etching it and then replating it.
I use a bit of vinegar on a cotton swab to knock down the pH, dab it off with water, let it sit around to dry out, and move on. When I’m feeling especially industrious, I add some Caig DeOxit Red to keep the surface from getting all gritty and intermittent.
You’re supposed to check all your batteries every year, but as nearly as I can tell that wouldn’t do any good. They look fine, right up until they get The Rot. Besides, that starts feeling a lot like work.