Tricks of the Trade: How to Clean a Spark Plug


They get all blackened and fouled and they don’t want to work right. It’s the carbon build up, you see and it’s unavoidable.

Of course they’re a small part and more than affordable, right? Sure! But who wants to spend money when they don’t have to?

The mistake a lot of folks make is believing that when a spark plug gets too dirty, it has to be replaced.

Well, I’m callin “hogwash” on that one, kids.

There are several ways to clean those bad boys off and get them back in the game, but there’s only one way I know to do it in record time, with the least amount of effort.

And that’s good for me, because I’m lazy. I’d take a bow, but I’d have to get up to do it.

So, let’s talk about fighting fire with fire.

For this job, you’ll need:

Heat resistant gloves

Eye protection

vice grip

Locking pliers


bench vise

 a bench vice and socket

Propane torch

sand paper

Emery cloth

Fire Extinguisher


You know that socket you used to remove the spark plug? Go ahead and secure that guy in your bench vice. Now, insert the spark plug into the socket – Electrode out.

bench vise with plug

If you don’t have a bench vice, you can use a pair of locking pliers. I recommend locking the socket with the pliers and setting them on a flat, heat resistant surface.

vice grip with plug

Now, we’re going to take the torch to the electrodes. But before we do that, were going to answer a few questions…

Where is your gas can? Where are your oily rags? You know the number for 911? Does anyone else know you’re playing with fire?


Ok. We’re going to heat the electrodes up pretty hot. The point is not to keep it glowing, but it may.

There’s no special technique here, just keep the flame on the the dirty parts. Essentially, what we’re doing is burning all that carbon off of the plug. There may be a few small embers but they shouldn’t present a hazard.

hot plug

As you maintain heat to the electrodes, you can actually watch the carbon flake away. Don’t worry about the heat ruining the plug. The spark plug is a catalyst for controlled explosions inside your engine, so trust me when I tell you that it’s going to be fine.

Just keep the heat on until the surface of the porcelain and the electrode are free of carbon.

When you’re done, the metal will probably have an ash grey color to it. That’s normal. Don’t sweat it.

Just let her sit a little and air cool. Do not use water to cool the spark plug!

Finally, a couple of light passes with the emery cloth will give us a nice, clean surface for the electricity to arc.

sandpaper plug

The last step should be to check the gap and you’re good to go.

If you have any sneaky little tricks of the trade, send them in! We’d love to post em in the Blog.

Until next time.


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Bill Brown

Bill Brown

Bill is the head of content creation for the LawnMowerPros Blog and DIY section. He’s been in the Outdoor Power Equipment Industry for years and he’s still learning new things everyday. You can often find him creating featured articles, DIY guides, videos, graphics and much more.