Cleaning a Corroded Car Battery Connector

A silver car on the road.
  • 1-2 hours
  • Beginner
  • 25-50
What You'll Need
Safety glasses or goggles
Baking soda
Adjustable pliers with insulated handles
Screwdrivers with insulated handles
Open-end, or box end wrenches
Small scraper
Cable puller
Battery terminal brushes
Rubber gloves

A corroded car battery connector is almost as common as is the car battery that is responsible for the corrosion. This corrosion is caused by condensing and deteriorating battery acid collecting on battery terminals and terminals of battery cables. Although this corrosion is not always visible without removing the car battery cable from the battery terminal, it can build up enough to interfere with the transmitting of electrical power from the battery to your car's electrical components. You can easily clean away this corrosion by following the directions below.

Step 1 - Use Safety Precautions

In working in the area around a car battery you will usually be working near sulfuric acid used by your car battery. This acid can damage your clothes, your skin, and even the paint on your car. Protect these surfaces from getting acid on them. Wear clothes that you don't mind discarding and rubber gloves that will protect your hands.

Step 2 - Neutralize and Remove Acid On Car Surfaces

Use a turkey baster to apply a solution of baking powder and water to the top surface of your car battery. Apply this solution slowly and carefully to avoid splashing acid. You'll know that any acid on your battery, battery cables, or battery terminals is being neutralized if you see a greenish foam form. When the acid is neutralized, that is, when it stops foaming, rinse the battery surface with water. If you see greenish deposits that remain after applying the solution, use a scraper or stiff bristled brush to clean off these deposits.

Step 3 - Disconnect Your Battery Cables

You'll find 2 cables connected to your battery terminals. Each of these terminals is about ¾ of an inch in diameter and will have a collar, or clamp, from the cable end that will be clamped over a battery terminal. These clamps are held tightly to the battery terminals with a bolt fitted through the clamp. Use an open-end wrench or box wrench to loosen this clamp. If the cable clamp fails to come loose, use a pair of pliers to grip the clamp. Then break the clamp loose by turning it. Slip the cable off the battery terminal.

Step 4 - Clean the Terminal and Cable Clamp

Use a battery terminal brush to clean off the corrosion from the terminal. If you don't have a terminal brush use a wire brush or sandpaper. Clean the inside surface of the cable clamp with a wire brush that is small enough to fit inside the cable clamp. Use a damp rag or sponge with the baking soda-water solution to wipe off these surfaces.

Step 5 - Replace the Battery Cable

Slip each battery cable clamp onto its terminal. Each clamp will be a different size and should easily slip over the right battery terminal, so be sure you have them connected to the right terminals. If necessary, tap the top of the clamp with a hammer to make it fit in place on the terminal. Tighten each clamp again with your wrench.