How to Clean Corroded Battery Terminals

Car battery maintenance is an important part of keeping your vehicle running smoothly. Here's everything you need to know.

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A few minutes






Corroded battery terminals can cause several problems with your car. They can prevent the battery from fulling charging, drain the battery (resulting in your car not starting), and can also cause major damage to the alternator. Cleaning battery terminals is an easy, inexpensive preventive maintenance measure you can do yourself in about 10 minutes.

Tools Required

  • 12-volt battery or power supply
  • Battery terminal cleaning tool
  • Cleaning rags
  • Eye protection
  • Water sprayer
  • wrench or socket set

Materials Required

  • Battery terminal cleaner
  • Battery terminal protective spray

Safety Note: A battery contains sulfuric acid that can cause serious burns. Always wear gloves and eye protection when working around a battery. Smoking, flames, sparks, or other ignition sources can cause a battery to catch fire or explode. Exercise caution when jump-starting or working near a battery with metal tools to prevent short circuits and sparks. If you come into direct contact with battery acid, flush with plenty of water and seek medical attention immediately.

Project step-by-step (6)

Step 1

Memory Saver Backup Battery

  • Having a 12-volt backup battery will save all the memory stored in your car’s computer, radio and clock.

12 Volt Backup BatteryFamily Handyman

  • Connect it directly to the battery terminals before disconnecting them. Or plug a 12-volt power source directly into a cigarette lighter or OBD II port.
  • It’s very important not to connect the positive and negative leads together or you will blow a fuse.

Plug Battery Into Cigarette LighterFamily Handyman

Step 2

Disconnect the Terminal Clamps

  • First, determine the positive and negative terminals. The positive (+) has a red cover or cable, and the negative (-) has a black cover or cable.
  • It’s very important to FIRST disconnect the negative terminal clamp from the battery post, using a wrench or socket, then disconnect the positive terminal clamp from the battery post.

Disconnect The Terminal ClampsFamily Handyman

Step 3

Cleaning the Terminals

  • There are a few ways to clean the battery terminals – some home remedies include Coca-Cola, baking soda, and hot water. You can also purchase battery terminal cleaning spray.
  • Clean both battery posts and terminals with the cleaner of choice.

Clean Battery TerminalsFamily Handyman

Clean Battery TerminalsFamily Handyman

Step 4

Apply Grease

Apply GreaseFamily Handyman

Step 5

Install Terminal Clamps

  • Always install the positive terminal clamp first, followed by the negative terminal clamp. Tighten clamps with a wrench or socket.

Install Terminal ClampsFamily Handyman

Step 6

Corrosion Prevention

Coat Terminals With ProtectantFamily Handyman