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The clamps that are attached to the car battery are corroded, I was told either of these liquids will work. Which one is better? Is there a how to guide on the exact steps I need to take? With my limited knowledge, I know...

Disconnect the battery (the order of the clamps matters I think?), Clean the clamps and ports, Wait, Reattach battery

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3 Answers 3

up vote 4 down vote accepted

What about a can of battery terminal cleaner? Should be available at any parts store (aerosol can). That plus a wire brush has always worked for me. As far as order of disconnection / connection, ground/black/negative is the first off and last on.

You could try cola or baking soda and water. They should work, but I suspect no better than a can of terminal cleaner. The cola will get rid of the corrosion but leave your terminals sticky. Maybe in an emergency, as Rory suggests, cola. Be careful with liquids around a battery, a short will ruin your day.

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Definitely use terminal cleaner - although if you are out in the middle of nowhere and can only find a can of coke then it can help remove gunk and corrosion in an emergency. Would be a weird kind of emergency though :-) –  Rory Alsop May 28 '12 at 16:13
    
Just he answer I was looking for! –  ironcyclone May 29 '12 at 16:28
    
I've never even needed the cleaner. Just the terminal brush has been enough. –  Brian Knoblauch Dec 4 '13 at 16:44

Baking soda/water works fine to neutralize the acid. Big puffy or crusty chunks of white or greenish corrosion around the battery terminals are indicators that the metals have been exposed to the sulfuric acid in the battery. This happens because the seal between the lead terminals and the plastic battery case degrades over time. General procedure:

Before clamp disassembly:

-Moisten the corrosion (don't wash it away)

-Liberally apply baking soda and wait a few minutes

-Make sure to rinse well when you're done, including the area beneath the battery, to prevent any un-neutralized acid from causing gradual damage/corrosion

If you want, at this point disconnect the clamps from the battery (negative first!) and continue cleanup. I like doing the pre-clean because it prevents me from having to expose my tools to the acid.

Note that distilled water is not electrically conductive on its own, and tap water is only very marginally more so. Battery electrolyte (acid) is conductive, and if it covers the battery's exterior surface between terminals or between the (+) terminal and the car's chassis, it will result in a 'short' which will drain the battery while it's at rest.

Therefore, it may be valuable to spread the baking soda over more of the case than where there is apparent corrosion to neutralize as much of the leaked acid as possible.

Finally, DON'T allow any of the basic material (baking soda) to find its way into the battery's case through the vents or whatever; this will partially neutralize the electrolyte inside and can significantly reduce the battery's capacity (although if it's leaking and causing corrosion it's probably not long before it's due for replacement, anyway).

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Use the baking soda and water, its cheaper than terminal cleaner and you probably already have it in your refrigerator. Terminal cleaner does exactly what it says it does, it cleans terminals, it does not neutralize acid. Coke is a last resort. The idea is to neutralize the acid, baking soda does this. Coke is an acid, not a base, it adds to the problem, not to mention you don't want ants in your engine compartment. Always disconnect the ground/black/negative/neutral terminal first, and reattach it last. Make sure the terminals are all the way down on the post for best contact. Use a wire brush to clean the terminals and the battery post. They sell brushes made for this at the parts store for less than five bucks. Can use a standard wire brush as well.

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