3 Proven Methods On How To Clean Spark Plugs

Spark plugs are essential components in petrol engines that enable the vehicle to run nicely and smoothly.  So it is crucial to keep the plugs clean to provide optimal performance. The way to avoid unnecessary replacements and keep them in good working condition is by cleaning them.

Cleaning spark plugs is one thing; knowing when they need cleaning is another. It is usually best to replace old and dirty spark plugs. What if you’re on a tight budget and can’t afford to replace them with new ones? Then, cleaning will suffice. It can keep your vehicle running nice and smoothly again for a few thousand miles.

In this article, we’ll discuss at length how to clean spark plugs using a blow torch, abrasives, and spark plug cleaner tools. However, it is essential to know when a spark plug goes bad.

How To Clean Spark Plugs

how to clean spark plugs with wire brush

Cleaning spark plugs is a mechanical task that every entry-level mechanic and DIYer can do effectively. In any case, there are various methods to clean spark sparks.

When planning on cleaning spark plugs, you need to remove them; first, there’s nothing like how to clean spark plugs without removing them. You need to access the plugs by removing them before choosing the method you want to use.

Removing Spark Plugs

Locate the spark plugs by tracing the ignition coil or spark plug wire. you find it challenging to locate the spark plugs in your vehicle, consult your owner manual – that’s the manufacturer’s blueprint.

 Once you locate the spark plugs, clean the dirt and debris surrounding that area to prevent them from falling into the plug holes when removing the plugs. Ideally, I recommend blowing the dirt and debris away with compressed air.

If dirt or debris falls into the spark plug holes while taking off the plugs, it could cause catastrophic damages.  When blowing off the junk with canned or compressed air, ensure you wear eye protection.

Remove the plug wires one at a time. This will help you put spark plug wires correctly to avoid engine stalling/backfiring and reduce the risks of something falling into the plug holes when you unscrew the plugs.

Removing all the plug wires simultaneously will not confuse you when reinstalling them. When removing high tension wires, hold it on the low boot firmly and gently pull it out. If any of the cables prove stubborn to come out, hold it firmly and twist it a little to loosen up.

 Get a spark plug socket and connect it to an extension and a ratchet handle. Put the plug socket in the spark plug hole and turn it counterclockwise to break free and unscrew the plug. The moment it’s free, remove the handle and unscrew it by hand.

Most spark plug sockets have rubber grommets that will grip the spark plugs and prevent them from falling when removing them out of the hole. When removing the spark plugs, watch out for debris and blow it off to avoid falling inside the cylinder head.

Method 1: Cleaning With Abrasive

Clean the electrodes with 220-grit sandpaper: There’s always a small pole sticking out of the end of a spark plug (the part that goes into the engine). It is known as an electrode. If it has carbon deposits or it’s discolored, get a piece of sandpaper and clean it gently until there’s no piece of carbon left on it.

Keep sandpapering the electrode until it looks like bare metal. It is advisable to put on eye protection while sanding. Sandpaper is one of the best spark plug cleaners in the market.

Clean the carbon deposits with a file: Sandpaper should be able to do the trick, but if it doesn’t, consider filling off the stubborn deposits with a file. Place the file on the gap between the plug body and the electrode and slide it back and forth.

Clean the threads with a wire brush: There are chances that you have grimes and oils on the plug threads. If there’s oil on them, it’s an indication of oil in spark plug holes. Clean the spark plug holes before reinstalling the plugs. Brush the plugs from a perpendicular angle to easily remove the deposits and debris on the thread. Then, turn and brush the plugs from a different angle.

Ensure you wear hand gloves when cleaning plugs with a wire brush to avoid poking yourself. The thread doesn’t have to retain its color to work, but you need to remove all the deposits.

Use carb cleaner: Carb cleaners are available in nearby auto shops and online stores like Walmart, eBay, and Amazon.

If you’re an entry-level mechanic, you may be wondering how to clean spark plugs with a car cleaner. Carb cleaners are used to clean carbon deposits, buildup, dirt, and junk on several auto parts effectively.

To clean with carb cleaner, place the spark plug on a clean surface like a vice and spray the cleaner on it. After spraying the cleaner, wipe it with a clean towel. Aside from cleaning, it dries quickly and leaves you with clean spark plugs.

If the carbon deposits prove stubborn to clean, use a wire brush and a carb cleaner. Once you’re done, wipe the plug thoroughly with a clean towel or rag to dry off the carb cleaner on it.

Repeat the process on all the spark plugs simultaneously. The first is to clean, then reinstall and socket the lead wire or ignition into that cylinder. If you’re asking how to clean spark plugs with vinegar or wondering how to clean spark plugs with petrol, the process is similar to carb cleaner.

It requires brushing off the carbon deposits on the plugs with a wire brush and soaking the plugs with vinegar or petrol for a few seconds.

Method 2: Using Blow Torch

cleaning spark plug with blow torch

A blow torch will make the spark plugs extremely hot. Hence, you’ll need to extend the length of the plugs by holding them with a plier to prevent burning your hand.

Hold the plugs with pliers on the end the ignition coil connects to. Hold the plug firmly and don’t squeeze it to avoid causing damage to the plug. The plier should only act as an extension. A bench vice is a better alternative to pliers.

Turn on the knob on your propane touch or gas, then place the ignition source in front of the nozzle or hit the ignition button. This will ignite and keep it burning. Turn the torch up until it starts generating blue flames.

The touch will burn off all the junk, debris, and oil on the spark plugs. Don’t be afraid of damaging the plugs; they’ll survive the heat without issues. Keep burning the plug while rotating it until the electrode and the end of the spark plug is glowing red.

Do not allow anything to distract you, and don’t let the torch burn anything else (burn only the threaded portion of the plugs). The burning process may take several minutes, depending on your torch and how hot it gets.

Allow the spark plugs to cool before holding them with your fingers. The plugs need to be cool before using them. You must be careful when dealing with spark plugs and a blow torch; the spark plugs will return to their standard color long before it becomes cool. To avoid burning off your hand, allow each plug to stay for 5 minutes before trying to reinstall it.

Remember, I asked you to clean the spark plugs simultaneously. When a spark plug is cool, reinstall it and plug in the ignition coils or high tension wire before moving to another one. Continue this process until you clean all of them. Do not clean one and leave others.

Method 3: Using Spark Plug Cleaner Tool

how to clean spark plug using tool

Another proven effective method of cleaning spark plugs is using a spark plug cleaning machine. The cleaner tool is designed to feed in air and sandblasts the spark plugs. This tool is pretty handy.

To use this tool, fix the airbag and tighten the clip, then plug in the air supply. Push down the button on the machine, socket the spark plug, and switch the mechanism to sandblasting. Keep shaking the plug so the cleaning tool will blast off all carbon buildup on it. When you are done with the blasting, switch the machine to air and blow off the debris on the plug.

I still recommend you blow the spark plugs with an air supply. You wouldn’t want debris to fall inside your cylinders.

Reinstalling The Spark Plugs

 Consult your vehicle owner’s booklet or visit the manufacturer’s website to know the specified gap measurement. Once you have ascertained the measurement, insert a spark plug gap tool on the gap between the electrode that sticks out and the spark plug body.

Measure the opening and know whether you should increase or decrease the gap by either prying the body further from the electrode or tapping it closer to the electrode until you get the exact specification.

Insert the spark plug and tighten it by hand. This is essential to avoid cross-threading the plugs. Threading the spark plug with a socket handle can wear out the threads. Hence, it is advisable to snug it by hand before torquing it with a plug socket.

Once you can’t move the plug by hand anymore, connect your socket wrench and torque it. However, you don’t have to apply too much force to it. Using too much can cause the plug to break in the cylinder head. If this happens, you’ll need to drop the head cylinder, leading to.

What’s next? Reconnect the ignition coil or spark plug wire. Hold the wire firmly on the boot and gently connect it to the plugs. You’ll hear a click that signifies the wire sits nicely on the plug.

If you don’t hear a click, that indicates the plug wire did not connect well on the plug and may pull off while cruising down the road. So, if the wire does not sit properly, pull it up and reinsert it while twisting it left and right.


Q: Can a spark plug be cleaned and reused?

Yes, of course. A spark plug can be cleaned and reused; if not, what’s the need for this article?  In any case, today’s high-end spark plugs cannot be filled but can be slightly blasted and clean. Using a wire brush, wd40, or spark plug cleaner tool will do an excellent cleaning.

However, cleaned or blasted spark plugs cannot give the same efficiency as new ones. Given that high-quality work plugs like ruthenium, platinum, and Iridium spark plugs only cost a few dollars, getting a new spark plug won’t tear your pocket.

Q: Can you use wd40 to clean spark plugs?

Wd40 is produced to remove carbon deposits and fights moisture on several auto components like spark plugs and plug cables. The acronym WD stands for water displacement. So, if any part of your system components is wet and you want to wipe off moisture, wd40 is the guy to use.

I know you will be wondering how to clean spark plugs with wd40. It’s as easy as using a brake cleaner. Loosen the spark plugs and place them on vice and spray the wd40 on it. Once you’re done with one side, turn the other side and clean it.

Q: Can you clean spark plugs without removing them?

You have to clean spark plug areas before taking off the plugs. However, cleaning a spark plug requires removing them to access the carbon buildup.

Q: How do you lubricate spark plugs?

It’s not all about applying grease on a spark plug, but how and where you use it counts. Since dielectric grease is an insulator, you need to apply it on the spark plugs alone sparingly. Do not let it touch the metal connector on the boot. Take the grease with cotton wool and apply only a tiny amount.

Apply a thin layer of the electric grease inside the boot via a circular motion. For optimum protection, you can apply a thin layer of grease to the ceramic coating of the spark plugs. Again, use it in the same circular motion. Make sure not to touch grease on the spark plug metal terminal. 

Q: What grease do you need for spark plugs?

Spark plugs use a specific type of grease. It requires only dielectric grease, which is a protectant like car wax. Dielectric grease is also used on several car components like battery terminals, lightbulbs, and spark plug boots.

Final word

When cleaning or replacing old spark plugs, if you see oil on the spark plugs wires, ensure you clean the spark plug holes to get efficient performance.

You’ll also need to inspect the spark plug cables; a bad spark plug could be the reason you’re cleaning or replacing an old spark plug. If it is the culprit and you fail to figure it out,  you’ll end up getting the same result even after a replacement until you change the defective cable.

At this juncture, this article has provided sufficient information on how to clean spark plugs. The process is simple, fast, and accessible.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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