A few drops of stop bath on a Q-Tip, perhaps?

Clean out as much as possible by manual methods, first. Carefully dab on some stop bath. The yellow indicator will tell you when the battery "juice" is neutralized. Use clean water to get the stop bath out. If used sparingly, there shouldn't be much to clean out in the first place. Right?

Use a gray, ballpoint pen eraser to polish any leftover corrosion off the contacts. Clean out the dust and eraser flakes. Dry well.

I've done this a couple of times before on both camera and non-camera equipment. Works for me.