How to Clean a Spark Plug

A tune-up is required at intervals between 60,000 and 160,000 miles on gas-powered cars, and replacing spark plugs is one of the major services completed during a tune-up. But if your engine floods or you have misfire issues that prevent your car from running correctly, the spark plugs might be fouled well before you reach that service interval.

Instead of replacing it, you can often clean a spark plug if the electrodes are still in good shape. Since spark plugs are usually $10 to $25 apiece, it’s an opportunity to save some cash and still get your engine running right. Here’s what you should know about how to clean spark plugs with three common methods.

Products You Need

For the DIYer, there are a handful of tools you’ll need as well as your preferred method for cleaning the spark plug. They include:  

Once you’ve collected your tools and products, it’s time to get to work. Expect it to take between one and two hours to remove and clean each of your spark plugs. 

How to Remove Spark Plugs

While it’s technically possible to clean a spark plug with combustion chamber cleaner to a certain degree, removing and cleaning them individually is the best and most effective method. Each vehicle will have its own specific process to remove them, but generally, these are the steps to follow. 


Locate the spark plugs on the engine. They are typically found on the top of the engine, near the center.


Remove the ignition coil or ignition cable boot from the spark plug. Gently pull the boot free using boot pliers if necessary. 


Use the spark plug socket to remove the spark plugs. The socket is designed to fit snugly around the spark plug and will protect the porcelain from cracking.


Attach the ratchet or wrench to the socket and turn counter-clockwise to loosen and remove the spark plug.


Repeat this process for each spark plug.


Inspect the spark plugs for wear or damage and replace if necessary. If they are fouled but not badly worn, use your preferred method to clean them.

When reinstalling spark plugs, be sure to torque them to the manufacturer’s specified setting with a torque wrench, and apply a small amount of anti-seize compound to the threads.  

Spark Plug Cleaning Methods

As long as the spark plug’s center and side electrodes aren’t worn and the porcelain insulator isn’t cracked, then cleaning it is likely to be successful. Here are three ways you can clean spark plugs and get them firing properly again. 

Abrasive Cleaning Method

Carbon, oil residue, and even fuel can foul a spark plug, preventing the spark from connecting between the electrodes. An abrasive such as sandpaper, a brillo pad, or wire brush can help remove any buildup on the center and side electrodes.  

Dry off the spark plugs and wipe any loose or sticky material off with a clean lint-free shop towel. Then, gently work your abrasive material of choice around the electrodes and wipe it clean frequently.  

Once you have a bare metal surface again, the cleaning is complete. From there, gap each spark plug to the manufacturer’s requirements before installing them. 

Blow Torch Method

A popular method for cleaning fouled spark plugs, particularly gas or oil-fouled plugs, is with a lighter or torch. Because of the extreme heat that can be generated, it isn’t always the wisest or most uniform method to clean a spark plug. However, it can and does still work in many cases. 

First, wear appropriate gloves to prevent the possibility of burning yourself. Then, grip a spark plug in pliers or something similar to hold it and pass a torch’s flame over the electrode. It’s best to use the very tip of the flame to concentrate the heat best. Only keep the flame on the spark plug for a couple of seconds or you risk damaging it. Repeat it until the contaminant is dry and burnt away. 

Then, let it cool and wipe the electrodes off before installing them in your car. 

Using a Spark Plug Cleaning Tool 

The most precise and effective method for cleaning spark plugs that is also gentle on them is by using a spark plug cleaner tool. A few varieties exist including electric-powered and ultrasonic cleaners, but the most popular is pneumatic. It contains an aggregate such as silica sand inside a cotton bag that gently dries out and busts up contaminants. 

Begin by pressing the threaded section of the spark plug into the cleaner, then attach the device to a compressed air hose. Press the button on the device for about three seconds at a time to blast the media inside against the spark plug, then check its condition. Repeat as necessary to clean the deposits off. Blow any dust off with compressed air, then re-install your spark plug. 

Find spark plug cleaners and replacement tune-up parts at AutoZone. Shop today to find the parts, tools, and accessories you need to keep your vehicle in top shape. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

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FAQ/People Also Ask 

What can I use to clean spark plugs? 

You can use an abrasive like sandpaper or a wire brush, a spark plug cleaning tool, or even a torch to clean a spark plug.  

Can a spark plug be cleaned and reused? 

Most spark plugs can last beyond 100,000 miles before they need to be replaced. If your spark plugs cause a misfire before their replacement interval, it’s often possible to clean and re-install them to fix the condition. 

Can you clean spark plugs with WD-40? 

WD-40 is an excellent cleaner for many things and can help break up deposits on spark plugs too. However, you’ll need to clean the WD-40 off of them very well before you install the spark plugs back into the engine. 

Can I clean a spark plug with alcohol? 

Rubbing alcohol can help remove deposits from a spark plug. It’s best used in conjunction with an abrasive. 

Will vinegar clean a spark plug? 

Vinegar is an excellent cleaner and can help break up deposits on a spark plug. It’s time consuming since it needs to soak for several hours, though. 

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