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How to Clean Car Battery Corrosion? Here Are 3 Simple Steps for You

The problem of car battery corrosion arises when your car sits in the garage idly for months. Corrosion can form in and on the battery’s terminals and around the battery cable ends, and the formation rate becomes faster when the engine and battery are not running. You can extend the battery’s lifespan and improve its performance if you regularly check and clean car battery corrosion. Let’s read this article to find out how to clean car battery corrosion.

What is Car Battery Corrosion?

Corrosion looks like a crusty, ashy substance that forms around the battery ports. It is created because of the chemical reaction that goes in the terminals and battery cable ends. Corroded ends won’t be able to supply power to the tools they have been connected.

how to clean car battery corrosion
how to clean car battery corrosion

What Causes Battery Corrosion? 

To help you know what causes car battery corrosion, here are top 5 reasons to check out:

1. Overcharging

Whether your battery is the flooded kind or the sealed, overcharging the battery can push the electrolyte out of the vents or cracks, thus causes corrosions.

2. Reaction in Copper Clamps

Copper is used to make the clamps that connect the wires and the battery. If you are good at chemistry, you will definitely know that copper is unable to corrode all by itself. However, the current which overpasses through it produces copper sulfate, thus resulting in corrosion on battery terminal.

3. Overfull Battery

Filling too much battery water into a battery is another reason making corrosion on battery terminal. And you know battery terminal are made of metals which can be corroded. Therefore, if you fill to much battery water into your battery, the excess water will comes out of the vents then corrode your battery terminals.

4. Electrolyte Leakage

One of reason causing battery terminal corrosion is electrolyte leakage. If a battery is not well-maintained, the electrolyte will leak out and accumulate on the battery terminals, causing corrosion.

5. Battery Age

If your battery is over 5 years olds, of course, you will see corrosion on it. So in this case, don’t hesitate to replace the expired battery by a new one.

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How to Clean Car Battery Corrosion?

You can learn how to clean corrosion off car battery by using both household items and professional-grade supplies. Here, we will show you how to handle with battery corrosion by both methods in 3 steps.

Step 1: Removing the battery terminals

How to clean corrosion off car battery
How to clean corrosion off car battery (Source: )

First of all, negative and positive cable ends need to be disconnected from the battery in order to clean the battery terminal connections properly.

Equipments needed:

  • Eye glasses for protection
  • Gloves
  • Battery terminal wrench

Caution: Car battery contains acid inside which may cause accidental injuries. Therefore, when working with a car battery, you have to wear eye glasses and gloves in order to protect yourself from acid.
To do this step, follow the direction below:

1. Loosening the battery cable ends. Disconnecting the negative cable is the first thing you have to do, then disconnecting the positive cable.
Now, it’s time to use the battery cable wrench. You place it on the battery cable end nut then twist it counter-clockwise.

2. Loosening the nuts. If your battery is a top-post battery, loosening the nuts till there is no tension on the clamp is what you will just need to do.

3. Loosening the cable end. If your battery is a side-post battery, you will need to loosen the cable end till it is removed.

4. Lifting the top-post battery cable end off the terminal. To do this, you should pry and wiggle the cable end off.

Step 2: Cleaning the battery

2.1 Clean the battery by using household items

If you wonder “How to clean car battery corrosion by household items”, here it is:

Clean corrosion off car battery
Clean corrosion off car battery (Source:

Equipments needed:

  • Baking soda
  • Water
  • A wire brush or a stiff-bristled brush
  • Petroleum jelly

As you can see, with this method, you don’t need to use specific materials to clean the battery terminals of your car. Some simple household things are enough for you to restore a proper connection and clean the battery of your car.

Using baking soda to clean corrosion off car battery (Source:
Using baking soda to clean corrosion off car battery (Source:

1. Firstly, you cover both battery terminals by baking soda. Sprinkle enough amount of baking soda powder to make a coat for terminals and the small area around the terminal as well.

2. Secondly, you need 2 tablespoons of water to pour on each terminal. After pouring water, you will see the baking soda reacting and bubbles will appear ferociously from the chemical reaction.
The chemical reaction between the mixture of acidic corrosion + baking soda + water on the terminals of car battery will neutralize the acid, thus it is safe for you to handle.

3. Do the same procedure on cable ends. You repeat the same procedure on the battery cable ends.

4. Scrubbing the terminals is the next thing you need to do immediately. After you do neutralizing procedure, next step is using a stiff brush to scrub the corrosion of car battery off. You can use an old toothbrush or a wire brush to scrub all around the cable end inside and out as well as the terminal of your car battery.

5. Rinsing with water. After you remove all the corrosion, next step is rinsing the cable ends and the battery carefully with clean water.

6. Drying the battery completely. After rinsing with water, you need to let your car battery dry entirely. Using compressed air is an effective way to blow make the battery dry.

Using petroleum jelly to protect car battery from corrosion attacks
Using petroleum jelly to protect car battery from corrosion attacks (Souce:

7. Place a thin layer of petroleum jelly on your battery terminal. You need to smear a thin layer of petroleum jelly on the cable end and the car battery terminal as well. The layer of petroleum will conduct electricity between the cable end and the battery terminal and also prevent corrosion appearing on the battery terminals.

Check out the video to know how to clean car battery corrosion in cheapest way: 

2.2 Clean the battery by using professional-grade supplies

Equipments needed

  • Battery terminal brush
  • Battery cleaner spray
  • Water
  • Grease or protective spray
Clean corrosion off car battery using a kit of specific materials
Clean corrosion off car battery using a kit of specific materials (Source:

With the kit of specific materials, you can easily clean your car battery in a professional way. Here below is how to do:

1. Spraying the cable ends. After disconnecting all battery cables, you use battery cleaner spray to spray on the battery terminals and the cable ends. Why you have to do this? Well, the spray will neutralizes the corrosion and acid on the battery. A lot of spays produced with a dye inside them that helps show up acid appearance. For instance, a yellow spray may change into purple if there is a presence of acid.

2. Soaking for some minutes. Soak the battery and the cable ends in the spray for some minutes. You may notice the color of the spray dissipate.

3. Spraying the cable ends and the battery terminals again. Using the cleaner spray to lightly spray the cable ends and the battery terminals again. If you observe that the color doesn’t change or there is a slight change, this means the acid is neutralized.

4. Rinsing with water. Spend water to rinse the battery entirely. Carefully clean spray off the car battery and the areas around it.

Caution: You should be careful when using battery cleaner spray as some dyes in cleaner spray will stain your paint another color.

Using battery brush to clean corrosion off car battery
Using battery brush to clean corrosion off car battery (Source:

5. Using a battery brush. After rinsing with water, it’s time to use a battery brush to clean the cable ends and the battery posts.

  • You should put the battery brush over the battery terminal and twist it from 3 to 5 times around the post if you have a top-post battery. Any corrosion on the battery terminal will be whisked away by the stiff wire bristles. Additionally, you can spend a stiff-bristled brush to do for a side-post battery.
Turn battery 3-4 times to clean corrosion inside the clamp
Turn battery 3-4 times to clean corrosion inside the clamp (Source:
  • Uncapping the battery brush and then inserting it into the cable ends. In this step, you should turn it at least 3 or 4 times around in order to remove all corrosion which is build up inside the clamp.

6. Spraying the car battery terminals. You spray the battery protector onto the battery terminals or you can make a thin layer of petroleum jelly onto them.

Step 3: Reconnecting the car battery terminals

In this step, a battery terminal wrench is all you need in order to make the cable ends reconnected.

Replacing the cables. First, you install the positive cable back into its position. For some top-post batteries, you will have to fully wiggle or tap the cable end down into its position.

Tightening the nut. You need to tighten the nut on the clamp to make it snug. Then try to add another quarter twist.

Placing negative cable. You reconnect the negative battery cable in the same way like what you do with positive cable.

Find out How to clean car battery corrosion by Coke in the video below

With these 3 steps above, hopefully you can get to know how to clean car battery corrosion. If you have any question about related to “how to clean car battery corrosion” or some car maintenance tips, feel free to give us a comment below, our auto experts will answer it for you.