How to Clean Car Battery Corrosion: Causes and How to Prevent it?

Battery corrosion can make your car jump start and stall even when the last trip was excellent. If you find it challenging to start your vehicle or you notice your car lighting system is affected, you may have battery corrosion. However, it is not a reason to worry because you’ll soon know how to clean car battery corrosion like a professional.

Careful observation will enable you to detect battery corrosion. You have to open your car’s hood and look out for a buildup around the battery terminals, and if you notice flaky substances on the car battery that may be blue, white, or green, you have battery corrosion.

A battery terminal can be corroded with time because of the battery’s chemical structure. It may not be harmful to the car when it’s still tiny, but lots of it can cause issues like a weak electric system, cause a warning light on the dashboard to come on, and lead to engine knocking.

What Makes a Car Battery to Corrode?

What is battery corrosion made of? It is made of hydrogen gas that is given off by the battery’s sulfuric acid. It undergoes a reaction and crystallization with other gases in the air to form the green, blue, or white, flaky substances that one can see on the battery terminal.

Car battery corrosion may happen quickly without warning or may take time to build up, but whichever is the case, it is necessary to know what causes car battery corrosion. Several factors can cause car battery corrosion, and they include:

clean car battery terminals

Hydrogen Gas: usually, the corrosion of a car battery happens when the sulfuric acid in a battery leaks out and releases hydrogen gas. The hydrogen gas then combines and crystalizes with other gases in the air. It often shows battery overcharge or undercharges.

Battery Connectors: some battery connectors can cause corrosion depending on the type you use because a reaction can occur between them and the sulfuric acid present in the battery.

 For instance, aluminum and copper connectors usually react with sulfuric acid, and such a reaction causes corrosion of the car battery.

Battery Overcharging: battery corrosion can happen in the positive terminal because of overcharging. Most times, what causes overcharging of a car battery is that it gets overcharged when hooking up the battery to a battery charger.

The overcharging can lead to corrosion because the temperature rises and causes an expansion in the volume of the electrolyte. This pressure caused by the expansion makes the electrolyte flow out to the terminals and causes corrosion.

The issue with the Alternator: can a bad alternator cause battery corrosion? Yes, because alternators ensure that your battery is charged when it’s in use. But if the alternator is bad, it won’t function well and may fail to be sending a strong charge to the battery.

As a result, the battery will not receive sufficient recharge. Such insufficient recharge causes the accumulation of white crystals on the battery, showing corrosion and pointing out that it needs a complete recharge.

The Terminal Used: car battery corrosion can be caused by the type of terminal used. Copper will likely react with sulfuric gases and form green or blue corrosion crystals with the aid of the electric current that flows over the copper clamps.

 Aluminum connectors will also react with sulfuric gases. The electric current that flows through its clamps will help it form crystals that are white in color. The reaction with the sulfuric gases shows that there is a leakage somewhere in the battery.

Electrolyte Leakage: a leakage in the electrolyte can also be the cause of a car battery corrosion, especially if the battery is the type where you always have to do electrolytes top up with water instead of the sealed type.

Damage to the battery or a lack of adequate maintenance can lead to the leakage of the electrolytes, which can cause corrosion. Corrosion also occurs when electrolytes spill on the terminals during battery refilling.

The Age of Your Battery: the age of a car’s battery can cause its corrosion despite how well you maintain the vehicle. Batteries’ life span is usually five years so, if your battery has lasted for about five years, then corrosion may be inevitable.

In some cases, some batteries may not last close to the five-year life span before you begin to notice a drop in their performance as a result of corrosion in their terminals. Such a condition is caused by many factors that cause your battery to age fast.

How to Clean Car Battery Corrosion Step by Step

Car battery corrosion does not look good, and it also stresses the driver, but you can remove it through careful cleaning. Ensure you have the necessary needed materials such as eye gear, an old toothbrush or wire brush for scrubbing, rubber gloves, and a battery cleaning agent.

clean car battery terminals

Baking Soda Dissolved in Water

  • Turn off the ignition to prevent electric shock.
  • Detach the black connecting cable first and then the red one.
  • Put the baking soda and water solution on the battery terminals, then use the brush to scrub off the corrosion in that entire area.
  • After scrubbing, pour clean water into the area to flush away the solution.
  • Return the clamps to their positions.

This baking soda and water solution does the trick of removing corrosion but if you want to know how to clean car battery corrosion without baking soda, then read on as there are other ways to get the job done and have your car battery free of corrosion. Some of them are:

Use Coke to Clean the Car Battery

Coke works well for cleaning a corroded car battery as it is carbonated and has a high acid content. So, when you have coke handy, you are ready to clean corrosion off your car. Let’s look at how to clean a car battery with coke.

  • Disengage the terminals correctly to avoid electric shock.
  • Gently pour the coke on the terminals where there is corrosion.
  • Scrub it off with the help of your brush.
  • After scrubbing everything off, pour enough hot water over it to rinse off the coke properly.

Note: while using this method, always ensure you rinse off the coke altogether to avoid your engine retaining dried coke that sticks to it. The sticky coke makes the engine appear dirty and attracts grime.

Clean the Car Battery with WD-40

When you don’t have other car battery cleaning agents, WD-40 can also do the trick of cleaning your car terminal, but you need to work a little harder. So, this is how to clean car battery terminals with WD-40.

  • Disconnect the terminals.
  • Now, spray WD-40 on the battery terminals and connections.
  • Rinse properly with hot water when you have left the WD-40 for some minutes.
  • Then, scrub with your brush and ensure all the corrosion comes off.
  • You may rinse it again till it is completely clean.
  • Dry the terminals and connect them to their place.

Clean the Car Battery with Vinegar

Vinegar is a strong acid that helps to clean car battery corrosion. It can be handy when you need to remove corrosion that refuses to come off easily, and you can combine it with baking soda for a perfect cleaning. How to clean car battery terminals with vinegar.

  • Disconnect the terminals.
  • Lightly cover the terminals with a sprinkling of baking soda.
  • Then, pour vinegar over it, and you’ll see it fizz.
  • Allow it to stop fizzing and to stay for some minutes.
  • Pour hot water over it to rinse it thoroughly.
  • Dry it and reconnect the terminals.

In this method, the fizzing that happens when you pour the vinegar on the baking soda breaks the grime and moves them away.

How to Clean Car Battery Terminals

Taking the steps outlined below is vital when cleaning your car battery terminals.

Turn off the car’s ignition and detach the battery: wear your rubber gloves and disconnect the negative clamp before disconnecting the positive. Inspect the battery for other signs of damage aside from corrosion; an example is cracks or ruptures, as such damage will mean that cleaning is not enough.

If the battery has no cracks or ruptures, ensure it’s not in contact with any metal to avoid shorting out the battery during cleaning.

Apply the cleaning product: if your cleaning product is baking soda, you apply it directly or as a solution. The direct method may not require a brush while you’ll need it in the solution application for adequate scrubbing.

You have to put a little hot water indirect use to make the corrosion wet and then pour a generous quantity of the baking soda on the affected place. You’ll let it sit for some minutes and then pour enough hot water on it to rinse off the corrosion.

The solution method requires that you combine a small quantity of baking soda and one cup of warm water. Scrubbing hard with a toothbrush that had already been dipped in the solution will help remove the corrosion. If some stubborn ones remain, a wire brush will do the trick.

You should follow the direct baking soda procedure for other battery cleaning agents that are not baking soda.

Rinse and Dry the Terminal, then Check: after applying the cleaning agent, it is important to rinse thoroughly with hot water. Next is to wipe the battery dry with a clean cloth and recheck the battery for any other form of damage.

Lubricate the Terminals and Reconnect: it is essential that you put a tiny amount of petroleum jelly in the terminals’ interior before connecting them to the battery again. The jelly will make the reconnection easy and help to avoid another corrosion.

How to Prevent Car Battery Terminal Corrosion

Carrying out regular maintenance of your car’s battery is vital so as to ensure that the vehicle keeps running. The reason is that corrosion usually takes place in the car battery when its acid leaks out and forms a buildup on the car battery’s terminal after some time.

Some of the ways to prevent car battery terminal corrosion include:

Petroleum Jelly: applying petroleum jelly to the battery terminals of your car will help to prevent corrosion. You can easily do this by wearing a latex glove, detaching the cables with the help of a wrench, and applying one tablespoon of petroleum jelly to the terminals.

Put the battery back to its position and always place the red cable before the black.

Dielectric Grease: applying a dielectric grease on the battery terminal is another way of preventing the buildup of corrosion there. To achieve this grease application, detach the cables in the battery and put the grease on both terminals. Such battery terminal grease is sold in hardware and auto parts stores.

Anti-Corrosion Washers: anti-corrosion washers will quickly help avoid corrosion from building up on the battery terminal of your car. These washers are pads with unique chemicals in them that work against corrosion and stop it from taking place.

An easy way to apply it is to detach the battery cables, slide the washers in there and replace the cables starting with the positive one and the negative.

Battery Terminal Protectors: these are pads of small size that you can fix between the battery and the connector. The battery terminal protectors are made from felt, which is a material that can prevent the formation of corrosion.

You can install battery terminal protectors by detaching the connectors from the battery terminal, sliding the protectors across the terminal, and connecting the battery to its place. The terminal to disconnect first is negative, while the positive comes first when reconnecting.

Clean the Posts and Connectors: if your car battery posts and connectors are not clean, conductivity could be lost between them. The loss of conductivity can make the battery undercharge and further lead to corrosion.

To avoid this, you should remove dirty posts and connectors, clean them thoroughly, wipe them dry using a clean material, and then reconnect them.

Do Appropriate Maintenance: regular and appropriate maintenance is suitable for your car battery. Consistency in car maintenance and getting other car services that your car needs help to ensure that all the car parts are running well.

This is good because car battery corrosion can happen due to other car problems, but such issues will be detected during regular maintenance.

Copper Compression Terminals:  these compression terminals are constructed from tinned copper and are designed to make the clamp fit nicely on the terminal. It reduces the formation of corrosion, especially in areas that reduce the flow of current from the battery to the connectors and the other parts of the car.

Always Examine Your Battery: the importance of constantly checking your battery for any indication of corrosion cannot be overemphasized. Running this regular check will help you notice some forming, and you’ll quickly clean off the corrosion by using any of the steps listed.

Aside from cleaning off the corrosion, a regular check will help you find the corrosion’s cause, and you’ll make the right step to fix it and have your car running well.

Frequently Asked Questions (FAQ)

Some of the questions that people repeatedly ask concerning cleaning car battery corrosion include:

Q: Is corrosion a sign of a bad battery?

Usually, the answer is yes, but it is not all the time. Car battery corrosion can be a pointer to many things, such as a buildup due to the reaction of the clamp’s copper and the electric flow in the terminal or a leak from the battery, which can be dangerous.

Also, a battery that has lasted for some years or the one about to go bad will usually have more corrosion than a new and good one. So, although corrosion does not always mean a bad battery sign, most bad batteries show corrosion as a sign. 

Q: Can you clean battery terminals while connected?

Yes, you can clean car battery terminals while they are connected. But, you have to ensure that the ignition is off for safety. Then, spray some hot water on the terminal with a spray bottle so that the water’s temperature will help in removing dirt from the terminal and making it clean.

In the absence of a spray bottle, you can pour the hot water from a reasonable height to create a jet spray, and it’ll still give you the same outcome. You can scrub with an old toothbrush or a wire brush to eradicate all residue, then dry with a clean towel.

Q: Can corrosion kill a car battery?

Yes, corrosion is capable of killing a car battery. The reason is that corrosion disturbs electric current flow and usually blocks it in the long run. It also makes the terminal and other metal parts of the battery depreciate with time.

So, when the terminal keeps deteriorating, and you don’t check the battery or take action to clean off the corrosion, it is very likely that the battery may stop working because of corrosion.

You can avoid this by always checking your car battery for powdery substances that are white in color. You can even examine it better by removing the rubber casting across the battery terminals and taking the necessary action when you see any sign of corrosion.

Q: Can battery corrosion keep a car from starting?

Yes, because the corrosion on the battery’s positive terminal may prevent the battery from having sufficient charge to start the car. Corrosion on the negative terminal blocks the charge, limits the clamp to terminal contact, and makes causes insufficient electricity.

Since the electricity is not enough, ignition becomes difficult as there is no flow of current. Thus, corroded battery terminals will prevent the car from starting.

Q: Does a corroded battery need to be replaced?

You don’t necessarily need to replace a corroded battery especially if you notice the corrosion early. The best action to take at the sign of car battery corrosion is thorough cleaning which you can do yourself and complete in just some minutes.

All you should do is get any of the cleaning agents such as grease sprays, vinegar, coke, wd-40, and the rest. Also, follow the cleaning steps carefully and the corrosion will be gone before you know it.

Nevertheless, it may be vital to replace the battery if has lasted for years and leaks out much acid. Also, if the corrosion eats too deep into the battery terminal, you may have to go for a new battery to ensure that your car keeps running and avoid huge mechanical damage.

Q: Can you use vinegar to clean battery terminals?

Yes, vinegar is great for cleaning car battery terminals. Vinegar is a powerful acid that helps to remove even a stubborn buildup of corrosion that stops or reduces battery performance and also affects the car’s function.

You can use vinegar to safely clean the buildup in the battery terminals and be sure that it won’t cause any damage. Vinegar is not harmful to the car battery terminal because its acetic acid is weak and gentle on the car battery.  

Q: Can you drive with a corroded battery?

It is not advisable to drive with a corroded battery because it could make the car difficult to start. It could get worse when you are stuck on the road and the engine won’t start because there is no flow of current to the ignition.

Also, it can be hazardous. The battery leaks acid which may explode and cause harm and even if it doesn’t explode, the acid that leaks out from the battery can spread to other parts of the car and cause damage that may be expensive to fix.

Instead of taking the risk of driving with a corroded battery, it would help if you take some minutes to work on cleaning your car battery and removing the corrosion to ensure safety and keep the vehicle running.

Final Words

Corrosion on your car battery is not something to be scared about, but it is something you have to pay attention to and take the right action. The best action here is cleaning the corrosion off your car battery to make it clean and avoid the negative effects that come with it.

So, if you have noticed corrosion in your car and want to know how to clean car battery corrosion, you can follow the steps outlined above to clean and prevent car battery corrosion, and your vehicle will be free from corrosion in no time.


Hi There, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I have been working as a mechanic for over fifteen years. I worked for a long time at Global Rebound Automotive companies (Toyota, TATA, BMW, Nissan, TVs, and Others ) as a Mechanic and Mechanics Supervisor.

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