When it comes to basic vehicle maintenance, understanding how to keep your battery running stronger and longer is one of the most important things you can do. Keeping your car battery’s terminals clean and removing corrosion can help to keep your battery running well for much longer than the average car battery, which can save you money and time.

There are lots of different ways to clean your car battery terminals, but not all of them are safe or effective. We will discuss some of the best and safest ways to clean your battery terminals so that you get the best results without putting yourself or your family members at risk of injury.

Throughout the rest of this article we’ll talk to you about how batteries work, what corrosion is and how it happens, and then we’ll give you step by step instructions on how to clean car battery terminals at home safely with the use of household products or special cleaners.

How Do Car Batteries Work?

A properly working car battery is an integral part of the efficiency of your car’s engine. The battery offers an electrical jolt that not only powers all of the electronics in your car, but also converts chemical energy into electrical energy that provides voltage to your car’s starter to get it running quickly so you can get where you’re going.


The terminals on your car’s battery are a crucial part of the process of getting your car running and keeping it running, as well as keeping your battery charged. The terminals are the place where energy leaves the physical battery. They are generally made from lead, which is a great conductor and is fairly resistant to corrosion. As the engine runs, energy is conducted through the terminals to keep your lights, radio, and other electronics running consistently.

What is Corrosion and Why Does it Happen?

Corrosion
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Image from Flagship One

We said earlier that car battery terminals are typically lead, which is naturally resistant to corrosion, but we know corrosion sometimes happens anyway, so what is it and where does it come from? Corrosion is what happens when chemical reactions between metal and its environment cause that metal to deteriorate.


Every type of metal can corrode, but some are more prone to corrosion than others. The rate at which corrosion occurs also has a lot to do with the type of chemical reactions happening and the gasses that come into contact with the metal. Some metals, called noble metals, very rarely corrode and are the only metals that you can find out in nature in their purest form.


When it comes to corrosion, there are some things that we can do to avoid it, but there are also a few different types you should know. It’s easiest to manage corrosion if you know what kind your system is at risk for and understand what each type means, so let’s look at those types. The types of corrosion we’ll talk about are as follows:

  • General Attack Corrosion
  • Localized Corrosion
  • Galvanic Corrosion
  • Environmental Cracking

The type of corrosion that occurs on a car battery is general attack corrosion, which we’ll go into detail about in just a moment. This corrosion occurs most often around battery terminals and is caused by hydrogen gas that is trapped under the hood of the car. This reaction can be worse in hot summer months or if your car’s engine is overheating.


General Attack Corrosion -  This is probably the most common form of corrosion you’ll see. It attacks the entire surface of a metal and is caused by either chemical or electrochemical reactions. General attack corrosion is sometimes responsible for metal failure, but it’s predictable, so we can often do a lot to prevent it from occurring.


Localized Corrosion - Localized corrosion attacks only pieces of metal structures. There are three basic types of localized corrosion, and they are pitting, crevice corrosion, and filiform corrosion. Pitting creates small holes in metal surfaces. Crevice corrosion occurs only in stagnant locations like under gaskets. Filiform corrosion happens when water gets under a coating on metal, like under paint on your car.


Galvanic Corrosion - When two different metals are connected in a liquid electrolyte (like salt water), galvanic corrosion can occur. Basically what happens, in this case, is the molecules in one of the metals are drawn to the other metal, which then leads to corrosion on or in one of the two metals, not both.


Environmental Cracking - This one is simple: when the conditions around the metal are extremely stressful, the metal can begin to crack, become brittle, fatigue, or weaken.

Car Battery Corrosion Prevention Tips


As we said earlier, it’s possible to prevent corrosion if you know what you’re doing. This is true of most situations including on your car’s battery. One of the simplest ways to prevent corrosion on battery terminals is to regularly apply a small amount of petroleum jelly to each of the terminals. This method is inexpensive and utilizes a product many of us already own.

If you don’t keep petroleum jelly on hand, or if you’d like to go a little more technical in your prevention technique, there are sprays you can buy to apply to your battery terminals that will also help prevent corrosion over time. You’ll want to apply this semi-regularly, especially just before winter to help increase your battery’s ability to start your engine in the cold, and just before summer when corrosion can get extremely bad because of the heat.

Safely Cleaning Car Battery Terminals: The Basics

how to safely clean car battery terminals
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Now that you know a little bit about corrosion, car batteries, and battery terminal corrosion prevention, it’s time to take a deeper dive into what to do when you notice corrosion starting to form on your batteries. Your car battery is only meant to live for three to five years optimally, so if it’s older, you will likely notice corrosion more often.


Noticing corrosion early is the best way to get it cleaned up before it starts to affect how well your engine runs, but we have tips and tricks to help you regardless of how much corrosion is on your battery. As long as there’s still some power, this guide could help you to get some extra life out of your battery. Let’s look at how to clean car battery terminals in a few different ways.


To save a little time and space as we go through the steps of how to clean your car battery terminals using various methods, we will give you the first three steps of every method here. One thing we haven’t included below is to ensure your car is off and your engine is cool before you begin this process. If your car is on or the engine is still hot, you will risk unnecessary injury.


Step 1: Locate Your Battery -  This might seem obvious, but in many vehicles, batteries aren’t where you’d think. Some are under the hood in plain sight, while others are located under the driver’s seat, in the trunk, or behind a tire. If you’re not sure where your battery is located, and you can’t see it clearly when you open the hood, check your car’s owner’s manual to help you find it quickly and easily.


Step 2: Lift the Terminal Cover(s) - On almost every battery you’ll find either plastic or rubber covers that are meant to protect the battery terminals. These covers will need to be moved for you to access the terminals and clamps that attach the battery cables to them.


Step 3: Disconnect the Battery - Although some batteries on newer vehicles differ, generally you’ll need to simply identify the negative terminal (typically labeled with a minus symbol or black terminal cover) and loosen the clamp. Then remove the clamp from the positive terminal (generally labeled with a plus symbol or red cover).

Safety Considerations Before You Begin​​​​ Work


Your skin and clothing don’t mix well with corrosive materials, so protection is key to keeping you safe as you dive head first into the world of vehicle maintenance. We suggest not only wearing safety glasses and gloves, as you should for pretty much any project, but also a smock or thick, protective clothing that you don’t mind ruining with holes or grease stains.

If at any point in the process of trying to clean your battery terminals you notice any leaks or cracks in your battery, know that it’s time to change the battery and take your car into an authorized mechanic as soon as possible. The same is true if you notice cracking or damage to the battery cables. These situations make it unsafe for you to continue work.

It’s always a good idea to check your owner’s manual before you start to mess with your battery. Some newer vehicles utilize battery power automatically when you are near them with a key and others may be connected to a jump box through what’s called an OBD port. If this is the case, you’ll need to read your manual to find out how to disconnect the battery in order to work safely as you perform your cleaning procedures.

Corrosion Cleaning Methods

Corrosion Cleaning Methods
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Now that you know the first few steps and how to stay safe, let’s talk about the specific methods you can use to perform the cleaning of the car battery terminals before we go into a step-by-step guide to getting your car back to running condition. We’ll consider any of these methods you choose to be step number four in the process.


Baking Soda Method -   We love when you can utilize simple household products to do routine car maintenance, and that is absolutely the case with this baking soda method for cleaning battery terminals. To make up your baking soda cleaner, you’ll simply mix two tablespoons of baking soda in a clean container with the same amount of water to create a thick solution.


With your solution in hand, grab an old toothbrush and head out to the garage to complete steps one through three from earlier. Once your battery is disconnected, use the toothbrush to get the paste onto the battery terminals. You should put on a decently thick layer for the best results. You should hear the mixture begin to fizzle as it begins interacting with the corrosion.


Wait a few minutes until the fizzle starts to slow, and then wipe off the solution. If necessary, you can use a wire brush to scrape off the excess residue, but you should be able to remove most of it with just your toothbrush. Finally, you’ll want to rinse the paste off of the battery using just water and a rag. Make sure to dry the area completely before beginning the steps to reconnect the battery.


Soda Method -  For years people have claimed that Coke is a great way to remove corrosion from battery terminals because it can easily burn through anything. What many people don’t realize, however, is that any cola will work for this purpose because of the high acidity of cola products. The acid in colas doesn’t react with battery acid, so it’s safe to pour onto the battery for use in this way.


Some people like the cola method better than the baking soda method because they don’t have to worry about making up a paste. To use the cola method, you’ll just need a 12-ounce can of your favorite cola and either a toothbrush or wire brush. After completing steps one through three from above, you can pour the entire contents of your can of cola over the engine terminals and wait a few minutes.


You’ll notice a similar fizziness to the baking soda method for a few moments after you’ve poured on your cola. When you let that subside slightly, you can take your brush and begin scrubbing to remove the corrosion from the terminals. Be sure to clean off your brush regularly until all of the corrosion appears to be gone.


With this method, it’s even more important to ensure you get all of the excess cola off of your battery. You’ll probably need more than just water to cut through the sugar in the cola, but don’t use a heavy duty cleaner on your battery, as it may cause damage. Make sure to rinse and dry your battery thoroughly before moving on.  


Battery Terminal Cleaner Method -  If you’re not quite adventurous enough to try the totally DIY methods we’ve talked about so far, your best bet is to head to your local auto parts store for some battery terminal cleaner. These products will all contain very specific instructions on how to prep your battery and how to use the products themselves.


Regardless of which product you use, you’ll likely still need a toothbrush or wire brush to get the excess corrosion off of your terminals, especially if there is a large amount of build up there. This method is by far the most expensive, but it also usually comes with a guarantee that it’ll work well and quickly to get you going again faster than the other two methods.

Final Steps

Final Steps
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When you’re done cleaning, rinsing, and drying your battery and terminals, you’ll need to go through a couple more steps to reconnect your battery and make sure things are working properly on your vehicle.


Step 4: Apply Battery Terminal Protectant -  Whether you choose a spray that is specially formulated from an auto parts store or you’d like to use petroleum jelly, you’ll want to apply something to protect your terminals from future corrosion before you go through the process of reconnecting your battery to your vehicle.


Step 5: Reattach Clamps -  You’ll reconnect the clamps to your battery in the exact opposite way in which you removed them. That means you’ll want to reattach positive side first. Remember, positive is indicated by red, and negative is indicated by black if they do not have plus or minus symbols.


Step 6: Replace Terminal Covers -  Now that your terminals are clean and your clamps are securely reattached, you can replace your battery terminal covers and any other coverings you may have had over the top of your battery. Once you’ve done this, you can close your car hood and pat yourself on the back for a job well done.

Wrap Up

We hope that this helped you to understand better how to clean car battery terminals safely and efficiently. We have a couple more tips for you before we go that will help you to finish the job in the best possible way.

Make sure any time you detach your battery from your car that you are wearing the proper safety equipment, and that you’re prepared to reset a few things once the battery is reattached. Quite often detaching a battery means losing your preset stations, having to reset your clock and other minor inconveniences. Keep your owner’s manual handy if you’re not sure you remember how to complete these tasks efficiently.

You should also always test your car after cleaning it to ensure the battery is hooked up properly and the car turns over as intended. You should notice a difference in performance right away if you’ve been having trouble getting the car to start quickly or noticed any other signs of corrosion before you looked under the hood.

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