[raz-0]

I was wondering why you would neutralize acid with another acid. It's because, according to the MSDS, the corrosive material is potassium hydroxide. A very caustic base. It's not a liquid, but a crystal. It's quite nasty, but at least in my experience with it, it's not quick like acid is, largely due to it being a solid. Also, from the sounds of the MSDS sheets, your risk is the fumes form the potassium hydroxide. That, if created in the right manner and quantity, is very nasty stuff as it works on your lung tissue rather than your much tougher epidermis. Priority number one if you rupture a battery is fresh air, not washing your hands. Rule number one while doing that is don't touch your eyes or any mucus membranes.

In ALL the MSDS sheets you listed, they recommend flushing with water. I'd concur with that as the only one that seems to have any acidic hazardous components are the li-ion batteries, and when they out-gas they also create caustic by products as well. Thus you want relatively neutral water.

Quite honestly, the only really hazardous batteries we deal with on a regular basis are lithium batteries. They are really mostly dangerous because of the temperatures achieved while out-gassing and the speed with which they can release all their energy. If one of them goes bad, you will KNOW not to touch it without being told. The important thing is fresh air and to put out any resulting fire.

ETA:

I also have a somewhat different opinion (or at least instructions) regarding battery safety.

1) In a particular cell size, don't mix chemistries for transport with the exception of primary, disposable alakalines. I.e. use NiCd or NiMh, not both. Do not mix chemistries AT ALL when in a device.

2) DO NOT UNDER ANY CIRCUMSTANCES mix lithium batteries with different impedances. This can cause one battery to become over drained before the device see's low power. This can be bad and cause out-gassing.

3) Try not to mix NiMh or NiCd batteries of differing charges. For transport (like in your camera bag) always have a means to keep "fresh" and "dead" batteries separated. Running a dead one in pair with a fresh one can overheat them just like a short. Because rechargeable lose charge simply with time, you can even run into issues with batteries that haven't been used in a device yet. This is why batteries like the eneloops are a good thing (tm).

4) DO NOT buy lithium batteries that are nor protected. Some cheaper 123A format cells are unprotected and unvented. That's bad. Rechargeable 123A cells are MOSTLY not protected. That is bad as well.

That being said, for most AA style batteries, the risk is primarily to the device they are in unless you surprise yourself like the OP did.

You don't need to instruct your toddler to douse daddy with the magic chemicals. If you see smoke, simply hold your breath till you open a window, and if you get anything on your skin rinse it off till you are bored out of your mind and don't touch your face until you do so.