I'm a bit ashamed to admit this, but I was just looking at my shelf and thought "Oh, I never removed the batteries from the Airlock Illumination Key that came with my copy of the MALAGAI 30 Year Anniversary Window Edition!". I just removed them, and to my surprise they had not leaked. I just checked them on a little battery tester, and I kid you not - they are still good! Almost ten years later. I'm kind of stunned.