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How to Clean Car Battery Corrosion: Step-by-Step

Power - by Joe Weber - updated on 11/10/2023

Battery with blue corrosion on one of the terminals

We've been talking about corrosion for a long time. That's because it's an easy thing to take care of and it has a huge effect on the life and performance of your battery. Whether it's in the sweltering summer heat or the bitterly cold winter, cleaning and preventing corrosion is a must-do task.

Tools Needed

  • Socket Wrench
  • Sockets (usually 10mm or 12mm)
  • Pliers
  • Gloves
  • Safety Glasses
  • Terminal Cleaning Kit (recommended) or Baking Soda and Water
  • Wire Brush (is included in the cleaning kit)
  • Memory Saver (Optional)

Clean Battery Terminals: Step-by-Step

  1. Safety first! Put on your gloves and eye protection before beginning.
  2. Pull the hood release and open the hood.
  3. Locate the battery.

    Expert Tip: Before you disconnect the battery, plug in a memory saver so you don't lose your radio presets, clock settings, anti-theft, keyless entry systems, cell phone settings, and other functions.

  4. Disconnect the battery. Starting with the negative terminal, remove the cable from the battery by unscrewing the bolt on the terminal connector.

    Use your socket wrench and hold the other end of the bolt with the pliers to prevent it from moving. Move the cable out of the way so it can't come in contact with the terminal. Next, remove the positive terminal connection using the same method.

  5. Examine the battery cables closely after disconnecting the battery. Take a moment to check for signs of wear or corrosion at the cable's connection point to the terminal. Additionally, evaluate the insulation for any dryness or cracking. Any cables showing damage should be promptly replaced by your mechanic.
  6. Remove the battery. While you absolutely can clean the corrosion without removing the battery, the safest approach is to take it out of the vehicle and place it in a shallow container or pan. This allows you to collect the corrosive residue as you clean as well as no longer having to work in such tight spots under the hood.
  7. Start scrubbing. The next step is to eliminate the corrosion on your car battery. Use a wire brush or scraper to clear away any dry, powdery corrosion on or surrounding the terminals and any accumulated dirt on the battery casing. Gently brush the corrosion, allowing it to fall into the container you've placed your battery in. Additionally, use a terminal cleaning brush to eliminate any debris or corrosive material on the terminals.

    Expert Tip: Don't forget to clean the terminal clamps too. Corrosion can build up on all metal parts connected to the terminal.

  8. Neutralize while you scrub. There are a couple of options when it comes to neutralizing battery corrosion.
    • There is a terminal cleaner spray that comes in your kit of terminal cleaning essentials. You can spray this onto the terminals (and connectors, don't forget about them) to neutralize the acid from the corrosion.
    • You can use a mixture of 1 Tablespoon of baking soda with 1 Cup of water. A mixture of baking soda and warm water serves as an excellent neutralizing solution. Dip a cloth or brush into the mixture and carefully wipe away the corrosion.

    Expert Tip: Don't pour the solution directly onto the battery to prevent any leakage into the cells, which could neutralize the sulfuric acid within, resulting in a damaged battery.

  9. Thoroughly wipe down and dry the battery casing, posts, and terminals with a microfiber cloth.
  10. Reinstall and reconnect the battery. Place your freshly cleaned battery into the battery compartment and secure it with the hold-downs. Reconnect the battery in reverse order, positive first, then negative. Make sure the terminal clamps are tight.

Prevent Corrosion from Forming

I know what you're thinking, "how do I prevent corrosion from forming in the first place?". There are a few things you can do to help keep corrosion at bay.

  • Install battery terminal protectors and spray the terminals and connectors with anti-corrosion spray. (Both are included in the terminal cleaning kit)
  • Avoid undercharging and overcharging.
    • Corrosion on the positive terminal is an indication that your battery is being overcharged. It could be a sign of a faulty voltage regulator and a mechanic should investigate.
    • Corrosion seen on the negative terminal indicates possible undercharging. A common cause for this is driving frequent short distances. When driving short distances the alternator isn't allowed the proper time to charge the battery.

For more information on preventing battery corrosion take a look at our blog article "What is Car Battery Corrosion and How Do You Prevent It?".

Extend the Life of Your Batteries

To get the most life out of your car or truck battery, proper maintenance is key. Checking for and removing corrosion, keeping it charged and limiting short trips are only a few of the maintenance tips in our blog "Car Battery Maintenance Tips and Tricks".

Stop by your local Batteries Plus today to have your car or truck battery tested, free of charge, to see if you need to look for a new battery. Batteries Plus carries a large selection of the best car batteries for your vehicle from brands like X2Power, Duracell Ultra, Optima and more.

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