How To Clean Car Battery Terminals: Tips, Techniques, & More

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We wouldn’t want to place a constrictor in the gasoline tank of our vehicle to deny the car the power it needs. However, when we have dirty car battery terminals, we are doing just that. To make sure your car has the get-up-and-go that it needs to get to your destination, having a functional and effective battery is essential. When your vehicle won’t start, there are a number of potential causes, and the first and simplest that we should look out for is the battery and the terminals atop it. If the battery is dead, it may need to be recharged and replaced after testing, but the issue could be as simple as dirty battery terminals. Read on to learn how to clean car battery terminals so that your battery will fire up without effort as long as it has the life to do so.

What You Will Need

To know how to clean car battery terminals and do it right, we need a very small list of tools and materials. The primary tool that we’ll need is a wrench, adjustable or sized to your battery’s clam, to loosen the nut on the clamp that attaches the cables to the battery. Beyond this, we require some electrical tape for a safety measure described below, as well as baking soda, a cup, an old toothbrush or a small soft-bristled scrubber, some water, a spray bottle, petroleum jelly, and shop towels.

Important DIY Tips

When your battery won’t start, the troubleshooting process begins.

Locate the Battery

It may seem the most obvious first step, but it must nevertheless be mentioned. Knowing where our battery is located is the first step in cleaning, repairing, or replacing the battery. In most American vehicles, the battery is under the hood, often towards the back close to the windshield. The battery is a large box or rectangle seated into a housing, atop which two large wires are connected and secured into place with tightening nuts.

For European cars such as BMWs, some models place the battery beneath the back passenger seats, accessible by removing the seat. Refer to your car manual to identify the location of your battery, and to learn what types of nuts are used on the terminals so you have the appropriate tool to assist you in the project.

Minimize Work and Risk

Before taking your battery out of the car to be tested at a car parts store, leave it in place and first give cleaning the battery terminals a try. The tips and techniques shared in this article may be all your battery needs to come back to full life. Before beginning, make sure the engine of the car is turned off. While the risk of injury on this relatively simple DIY Project is low, turning the engine off further minimizes the risk of harm.

Techniques for Cleaning

Knowing how to clean car battery terminals is achieved through learning a few simple steps that will take your battery terminals from coated and non-conductive to glimmering domes of electrical conductivity.

Step 1 – Locate Battery, Turn Off Engine

The first step as mentioned above is simply shutting off the engine. Doing this removes the charge from the battery and reduces the likelihood of shock or injury.

Step 2 – Cable Removal

The next step is to loosen the nut that holds the negative cable in place. While this can sometimes be done by hand, most likely you’ll need a wrench to achieve the loosening. One the negative cable has been loosened, remove it from the battery. We’ll then repeat the process with the positive battery cable, loosening the nut then removing the cable.

Pro Tip:

When you’ve removed the cables from your battery, it is best to keep them from crossing to avoid any electrical charge risks to your vehicle and to prevent the potential of the cables touching opposite battery terminals which can lead to a shorting out or even explosion of the battery. Keep the electrical tape on hand, and as you remove the cables one-by-one, wrap their exposed metallic ends in electrical tape to ensure that they do not come into contact with anything we’d rather they not.

Step 3 – Initial Assessment

After having removed the cables, it is time to consider the current condition of the battery. Assess the battery carefully to reveal whether there are any obvious cracks or leaks. If there are, it may be time to simply replace the battery, or in the least bring it in for a professional opinion at a car parts store or mechanic. Once we’ve confirmed that the battery seems to be solid and free of leaks, we move on to the cables.

After assessing the battery, we move on to a consideration of the cables and clams. See if there are any tears or rips in the cables that could be causing shorting out or other electrical issues. If there are tears present, it is best to have the parts replaced, as such issues generally cannot be repaired. A short-term partial solution may work to prevent shorting issues. For instance, if there are rips or tears apply electrical tape to seal in any exposed wire. This however is a temporary solution that may not be effective at all, so it is best to replace any parts that seem worn or damaged when it comes to the battery cables.

Having inspected the battery body and cables, the next step in how to clean car battery terminals is to assess the clamps themselves. Are they still capable of being tightened? Is the nut still in place? If the answer to either of these questions is no, then it is time to purchase new clamps, which often come attached to the cord.

Step 4 – Cleaning Solution

The next step prior to the actual cleaning is to create the cleaning solution, a central step in how to clean car battery terminals. To make the solution, mix a tablespoon of baking soda with a cup of water, and get an old toothbrush to use. Dip the toothbrush into the mixture.

Step 5 – Cleaning

Once we’ve assembled our baking soda and water mixture, it is time to clean the battery terminals and clams. Dip the toothbrush in the baking soda mixture and begin scrubbing, dipping it again into the baking soda throughout the process. Scrub away on the battery terminals and connectors to scrub away the build-up that you’ll see on the battery. Removing the majority or all of the corrosion is the most effective way to increase the conductivity of your battery and its connectors. Continual soaking of the toothbrush in the baking soda will improve upon the outcome.

Step 6 – Rinse and Dry

Once we’ve finished scrubbing, we’ll then use the spray bottle that we’ve filled with water to rinse away any residue we have built up from scrubbing. Make sure that all baking soda and corrosion is washed away as a failure to do so may lead to our having to do this project again all the sooner. After all the corrosion and baking soda has been rinsed off, we’ll use the shop towel to dry off the connectors, nuts, and terminals. Make sure to dry them thoroughly and take care to not leave residue or lint behind from the towel or rag that you use.

Step 7 – Lubricate

With the petroleum jelly, lubricate the terminals a bit to provide for ease of reconnection in addition to conductivity.

Step 8 – Reassemble

The final step is to reattach the cables to the proper terminals. To minimize the risk of malfunction or the development of problems, first, remove the electrical tape from one connector, attach it, then remove the electrical tape from the next and reconnect that connector. In doing so you can control and reduce the potential of cross-contact and shortages.


In the event your car is having trouble starting, and it is clear that you have corroded battery terminals that could be the cause, but you don’t have any of the tools or supplies you need, there is a quick-fix alternative. Pour cola, whether Coca-Cola, Pepsi or otherwise, atop the terminals then allow it a few minutes to sit before rinsing it with water. This can quickly and easily remove enough of the corrosion to achieve a connection. This may work to get you there, but when there’s time the full process should be completed.


Knowing how to clean car battery terminals is an important aspect of preventative maintenance. Keeping your car battery terminals clean and free of corrosion and debris will keep the conduction active and the electrical flow moving. If you have clean battery terminals and your car will not start, the first troubleshooting step has been performed, and we know that further inspection of the battery, the starter, the alternator, or other parts is necessary.

How to clean battery terminals is a relatively simple process, and one that should be incorporated into preventative maintenance efforts once or twice each year to ensure that the terminals are clean, conductive, and not the source of any battery-related problems.

For more tips, techniques, and tutorials on how to keep your car running hard and shining bright, check back to Keeping Cars Clean.

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