How to Clean Car Battery Corrosion

If your car or truck is having a hard time starting, check your battery for corrosion. Battery corrosion is a common issue that that can lead to starting problems or even prevent your vehicle from functioning properly.

Corrosion is often caused by gases escaping from the battery acid, which react with the metal terminals. The buildup of battery corrosion around your battery posts can disrupt the flow of electricity from the battery to the cable. Since the cable is what carries the power from the battery to your car or truck, this can stop you cold.

Over time, this can lead to poor electrical conditions, starting problems, and even battery damage. Regular maintenance and cleaning can prevent these issues, ensuring your car starts smoothly every time. The good news is that it’s not hard to clean up battery corrosion. This guide from Blain’s Farm & Fleet will walk you through the process with clear, actionable steps and safety tips.

What You’ll Need

Before you begin, gather the following tools and materials:

• Gloves: Rubber, latex, or nitrile to protect your skin.
• Safety Glasses: To protect your eyes from splashes. Choose a pair that’s not shaded, as it can be dark under the hood.
• Brush: A toothbrush, wire brush, or battery terminal cleaner all work well.
• Baking Soda: Acts as a neutralizing agent.
• Water: Works best when it’s hot. Distilled water is preferred.
• Container: For mixing the baking soda solution. A measuring cup works nicely.
• Washcloth or Shop Towels: Clean, non-cotton preferred.
• Wrench: A ratchet with at least a 6″ extension or an extension wrench is best for reaching down to loosen the battery mount.
• Pliers or Vise Grips: You may need them as you loosen and tighten the clamps on the battery cables.
• Dielectric Grease or Battery Terminal Protectant Spray: To prevent future corrosion.

Step-by-Step Cleaning Guide

Step 1: Safety First

Put on protective gloves and safety glasses before you begin. This will protect your skin and eyes from any harmful chemicals.

Open the vehicle’s hood, and ensure the engine is off before moving on to the next step.

Step 2: Remove the Battery

Using a wrench, carefully disconnect the battery terminals. Always remove the negative terminal first, followed by the positive. This prevents any accidental electrical shorts.

After you’ve disconnected both terminals, you’ll need to take the battery off the hold-down and/or loosen the bracket at the battery’s base that holds it in place. These can be hard to reach, so you may need to use the ratchet with an extension to help.

Carefully take the battery out of the engine compartment, and place it on a stable surface away from the car. This way, you won’t risk splattering acid onto your car when you clean it.

Step 3: Prepare the Cleaning Solution

In your container, mix 1/3 cup of baking soda with 2/3 cup of water. Stir until the baking soda is completely dissolved. This solution will help neutralize the battery acid and dissolve corrosion.

Step 4: Soak and Clean the Cables

Dip the ends of the battery cables into the solution, and let them soak for a few minutes. Use a brush to scrub away any remaining corrosion. Rinse the cables with clean water and dry with a towel.

Usually, only the positive cable and post corrode, but check them both anyway. Also inspect the cables to make sure there are no breaks, cracks, or fraying. If you see any of these, you should replace the cable and clamp.

Step 5: Clean the Battery Posts

Using a washcloth, apply the baking soda and water solution to the battery posts. Scrub away any corrosion, taking care not to let the solution enter the battery itself. Since it neutralizes acid, you don’t want any to get inside your battery. If you can’t get the corrosion off with the cloth, use your brush.

Be careful not to splatter any of the battery corrosion. It can eat holes in fabrics and cause corrosion on metals that it lands on. Take the time to check your battery. If you see any cracks or leaks, you should replace it immediately.

Step 6: Reassemble the Battery

Make sure your battery posts and cables are completely dry before proceeding. Place the battery back into the compartment, reconnect the positive terminal first (red), then the negative (black). Tighten the clamps securely, but don’t overtighten them.

Step 7: Apply Protectant

Cover the battery terminals with battery protectant spray or dielectric grease. This layer will help prevent corrosion in the future by insulating the metal from air and moisture.

Step 8: Test Your Work

Start your vehicle to make sure the battery is hooked up correctly. If the car still doesn’t start after this, you may need a new battery or have another problem.

Even if it does start, you should take it in to have your battery tested. Battery terminal corrosion can be a sign of other problems with the battery, or even old age.

Safety Precautions

• Always work in a well-ventilated area to avoid inhaling any fumes.
• Never smoke or use open flames near the battery, as hydrogen gas is highly flammable.
• Dispose of any cleaning materials properly to prevent environmental harm.

Preventing Future Corrosion

To maintain a corrosion-free battery, regularly inspect and clean the terminals. Applying a protective spray after each cleaning can significantly reduce corrosion buildup. You can also apply a thin layer of petroleum jelly to the car battery terminals. This creates a barrier against moisture and slows down corrosion.

By following these steps and maintaining regular checks, you can ensure your car battery remains in top condition.

As always, we recommend visiting your local auto mechanic if you’re not comfortable working on your own vehicle or if you notice frequent corrosion or other battery issues. Our skilled, trained mechanics in our Automotive Service Centers are always happy to help.

For more tips on caring for your vehicle, check out our other Auto Batteries articles.