How to Clean Battery Corrosion

How to Clean Battery Corrosion Advance Auto

The question of how to clean car battery corrosion as efficiently and safely as possible is one that dates back to the first lead-acid batteries used for cars, trucks and other vehicles. If you have a little experience tinkering with your car, you already know just how important your battery is. Your car can’t start without it, and corrosion can impair the normal functioning of your car’s electrical system, and may even impair the connection to your battery or destroy your battery entirely. Leaving corrosion unchecked will cause problems over time.

battery lifespan graphic

Battery Corrosion's Effects

Before considering how to clean battery corrosion, it is essential to understand how corrosion can affect your vehicle. While in small amounts it simply reflects your car’s normal wear and tear over the years, corrosion can get worse especially when subjected to higher temperatures during the summer months. Small amounts of corrosion are not usually a problem. However, as the problem worsens, larger buildups may form that will act as an insulator that will prevent the battery from accepting or delivering a charge. You might have a hard time starting your vehicle at first, and accessories like your radio and AC could occasionally remain without power. If the problem continues to persist, your car’s on-board computer will also be affected, and it may even fail entirely.

Advance Auto Parts stores offer free battery testing and installation*.

Removing the Cables

Regarding how to clean battery corrosion efficiently, you have to start by correctly disconnecting the battery. This task can be tricky, since you have to avoid unwanted power spikes and make sure any corrosion present on the clamps won’t impair your efforts. Before starting, determine the exact configuration of your battery. The terminals might be on the side, in which case you will need a 5/16-inch wrench to loosen the cable nuts. Otherwise, a more common configuration with the terminals at the top will require a 3/8 or possibly a metric-sized wrench. Always remember to loosen and remove the cable on the negative terminal of the battery first, and do NOT let the wrench come in contact with the positive terminal. You may find a socket wrench to be easier to use for this task.

How to Clean with Baking Soda

The issue of how to clean battery corrosion has to be addressed with great care. Before starting, you’ll need to make sure there are no tears or cracks found on the battery or on the cables. If you find cracks on the battery itself, that’s a bad sign; you’ll have to replace your battery. The cables or clamps may also be replaced, if their condition is bad enough to risk preventing a proper connection. If the only problem is the corrosion, start by mixing a tablespoon of baking soda with 250 ml of hot water. Use an old toothbrush by dipping it into the mixture and then scrubbing the top of the battery and the terminals with it. You can choose to dip the cables and clamps into the baking soda to remove additional buildup more easily, and if the toothbrush isn’t enough, try a battery terminal cleaner brush to remove all the corrosion. These tools include a skinny wire brush (for the inside of the clamps) and a recessed brush that can fit directly over the posts for a thorough cleaning. 

Finishing Tasks

After finishing your cleaning tasks, dry everything off using a disposable rag. Replace the negative and positive clamps in the reverse order you used to remove them (positive first), then use petroleum jelly or grease on the terminals to prevent the buildup of new corrosion. Specially-formulated anticorrosion grease is also available at Advance. These tasks should be added to complete any guide of how to clean battery corrosion responsibly and efficiently.

Other Considerations

A small amount of corrosion won’t prevent your car from starting in most cases. But if that’s what is happening, cleaning the battery terminals and clamps may not do much, and you’ll have to first test your car battery to find out what the real problem is. Also, if you purchased your battery more than 3-4 years ago, it may be getting toward the end of its service life, even if it still seems to be working well. Advance Auto Parts offers several levels of DieHard batteries to fit most vehicles. The question of how to clean battery corrosion, however, is an important one at all times, since corrosion can affect newly purchased car batteries as well.

Find an Advance Auto Parts store close to you.


*Car battery testing and installation available on most automotive vehicles, at most locations, unless prohibited by law.

Last updated September 23, 2021