How to Clean Car Battery Corrosion | Step-by-Step Guide

Have you ever tried to start your car only for it to stall despite running just fine on the last trip? Most of the time, it's a simple matter of having corrosion on and around the battery terminals. This can weaken or stop the battery's electrical system, which can be harmful. Fortunately, its a pretty easy fix if you know what to do.

You only need a few things that can be found laying around your house or garage. After that, just follow these four simple steps on how to clean car battery corrosion.

Let’s dive in...

Things you will need

You will always need these things when cleaning corrosion:

  • Rubber gloves

  • Cleaning product*

  • Warm water

  • Toothbrush and/or wire brush*

  • Rags or paper towels

  • Petroleum jelly

  • Additional tools

*There are two popular choices for the main cleaning product: baking soda or battery cleaner. Baking soda can be found in practically every grocery store or on Amazon (you may already have some too). Battery cleaner is usually only found in auto stores or on Amazon.

The only differences between the two are that baking soda is cheaper and battery cleaner tends to yield better results. Both have similar steps in the application process, but using baking soda does require a toothbrush and/or wire brush.

*Most people use a toothbrush, you can use a wire brush to get rid of any excess residue.

How Does Battery Corrosion Affect Your Car

Corrosion isn't good for your car, that's for sure. But a small amount is considered normal since wear and tear are inevitable on any vehicle that see's road time. However, if you let it build up over time it can form a thick crust over the terminals that makes it hard for your car car to connect to the battery. At first this may look like your radio and other smaller electronics turning on and off or going without power. If it continues to build you may end up losing the connection to your battery entirely until its properly cleaned. It can also affect your cars on-board computer causing it to shut off entirely until cleaned.

Cleaning Your Battery With Baking Soda & Vinegar

If you find yourself dealing with extra stubborn corrosion that doesn't come off with just baking soda, try the baking soda and vinegar method to clean your battery terminals. Vinegar is a powerful acid which can break down corrosion pretty quickly when combined with the fizzing action of the baking soda. To use this method, first make sure your terminals are disconnected. Then simply sprinkle baking soda powder on your terminals liberally. Next pour the vinegar on the terminals and baking soda and let it sit. When you pour the vinegar on the terminals you'll see it fizz. Similar to peroxide the fizzing action breaks up and moves the dirt and grime out. After it sits for a few minutes and its done fizzing, rinse it clean with hot water and follow the remaining steps from below before reconnecting your cables.

Cleaning Your Battery With WD-40

Some people use WD-40 to clean their car terminals. This can work well but will require more elbow grease. To use this method, make sure your terminals are disconnected. Then you'll spray WD-40 on each of the battery terminals and the cable connections if they're also covered in grime. Let the WD-40 sit for a minute then rinse with hot water. You'll probably need to scrub the corrosion off with a wire brush or toothbrush in addition to rinsing. You may also need to repeat the process a few times to get it fully cleaned. Then follow the steps below for drying and reconnecting your terminals.

Cleaning Your Battery With Coke

Coke is very acidic and carbonated so it makes a perfect battery cleaner. To clean your battery corrosion with coke, you'll first need to disconnect the terminals to prevent any electric shock. Now you'll simply pour coke over the terminals and connections a few times. Then take a wire brush to scrub everything clean. Once it all looks good, rinse thoroughly with hot water. We don't recommend this method for most people because if its not thoroughly rinsed then you'll end up with sticky dried coke in your engine. These spots will attract dirt and grime which can resemble oil spray and give the impression of a leak or broken hose. It also makes your engine look dirty which you might not like - especially if you're in a newer car.

Steps to Clean Your Car Battery Terminals

Step 1: Turn off the car and disconnect the battery

With your rubber gloves on, carefully remove the negative clamp before the positive one.

Next, check the battery to ensure there are no cracks, punctures, or signs of damage other than the corrosion where the clamps were. If there is damage, then the cleaning probably won’t do the trick and you’ll need a new battery.

If the battery looks fine, then make sure that it's not touching any metal since it may short out the battery while you’re cleaning it.

If there is corrosion on the terminal clamps, clean them the same way, but make sure they’re not touching the battery or other pieces of metal.

Step 2: Use the cleaning product

If you’re using baking soda, there are two types of application: direct and solution.

If you are using the direct method, you probably won't need a toothbrush or metal brush, unlike the solution method.

Direct use is when you pour a small amount of hot water to moisten the corrosion before pouring a good amount of baking soda on the area. Then, after several minutes, you slowly pour more hot water over the area, washing the corrosion away.

To use a solution, mix a tablespoon of baking soda and a cup of warm water. Using a toothbrush that has been dipped/soaked in the solution, scrub away the corrosion until the bulk of its gone. Then, if needed, use a wire brush to take away any excess.

If you're using battery cleaner like Permatex Battery Cleaner, follow the directions. Most of the time, they are similar to the baking soda direct method.

If you're cleaning the terminal clamps, any of the cleaning solutions should work the same way.

Step 3: Rinse, Dry, and Inspect

Make sure any residue is washed away by rinsing again with plain, hot water. Once the areas clear of any corrosion, take a clean, dry cloth and wipe the entire battery until its dry.

Before the last step, make sure to look over the entire battery one more time for additional corrosion or damage to the battery. If there is corrosion, repeat the cleaning process. If the battery is damaged, get it inspected by a professional. If your battery is covered in gunk, you might want to consider steam cleaning your engine and battery as well.

This step should also be used for the terminal clamps. If there is damage to the clamps, contact a professional.

Step 4: Lubricate or protect the terminals before reconnecting

Before the terminal clamps are reattached, use a small amount of petroleum jelly inside of the terminals before reconnecting them to the battery. This will help you reconnect them and prevent future corrosion. Use a different rag to apply, says Meineke.

Of course, there are specific products like CRC's battery terminal protector that’s said to last longer and prolong the battery life. Like the battery cleaner, it's not that expensive, but petroleum jelly is the cheaper option and works fine.

Make sure you connect the positive terminal first before the negative terminal. Then put the junction covers back on and turn the car on. If the car is still experiencing problems, it may need to be looked over by a professional.

All in all, if you have battery corrosion build-up, as long as you have the needed items, it can take as few as fifteen to thirty minutes to fix and be back on the road again.

If you do need something from the list like the wire brush, which can be expensive in stores, check out products on Amazon which usually sells cheaper packs of brushes.

Have a question about the process? Leave a comment below. Remember, all you have to do is:

  • Disconnect the battery

  • Clean and scrub

  • Rinse, dry, and inspect

  • Lubricate, reconnect, and turn on

Those are the four simple steps on how to clean car battery corrosion in less than a half hour.