# Best way to clean a spark plug



## t_andersen (Dec 19, 2007)

What's the best way to clean a spark plug that is fairly new and looks mechanically ok but is black?

White spirits?

I believe that caustic soda removes soot from stove windows, so that might work for spark plugs too?


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## windthrown (Dec 19, 2007)

I usually just replace the plugs if they get fouled. They are cheap. Rarely happens though. I use NGK plugs in all my engines. 

Also a bit of emery paper will clean off the electrode tip and the prong. That is about all you need to clean up, the engine firing will do the rest. More important, find out why your plugs are turning black.


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## ShoerFast (Dec 19, 2007)

Dito

Toss them, there cheap. 

You can clean plugs, spray out with carb or brake cleaner and boil/burn them out till there glowing. But your taking a chance of cracking the porclin and if that brakes during usage, your jug is screwed. 

Same with abrasive cleaners, that sheet falls in th ejug and scores it. 

Just my .02 cents worth,,,,, I don't think i have a cheep engine that dose not have a plug that i cleaned at some point.


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## niv (Dec 19, 2007)

I agree with shoerfast carb cleaner em real good and GENTLY burn em out. This will buy you some time until you can go get a new one.


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## romeo (Dec 19, 2007)

I don't clean them with any more than a wire brush, if it fires its good, if it fails its trash. I have used a propane torch to clean fuel fowled plugs for the kids dirt bikes at the track. But that is only an "emergency-race-starts-in-5-minutes-technique".


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## brncreeper (Dec 19, 2007)

oven cleaner works for me.


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## Sprig (Dec 19, 2007)

romeo said:


> I don't clean them with any more than a wire brush, if it fires its good, if it fails its trash. I have used a propane torch to clean fuel fowled plugs for the kids dirt bikes at the track. But that is only an "emergency-race-starts-in-5-minutes-technique".


Yup, agree with you, a fine wire brush is all you need and make sure all the crud/debris is either blown out with air or washed with a bit o' fuel, check gap and plunk it back in if it looks good. Never have found a use for old ones except ta make your toolbox look fuller 



Serge


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## wkpoor (Dec 19, 2007)

There is cheap plug blaster on the market that works great. They look practically new when cleaned in one of these. Don't use sand, its a special plug blast material. Works with air pressure. I've had one for yrs. Yes plugs are cheap but it will keep you going when the stores are closed or too far away to justify the trip.


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## jhellwig (Dec 19, 2007)

You could buy 20 spare plugs for what that hokey plug cleaner would cost. Spare are just as cheap as replacing a plug.


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## oneoldbanjo (Dec 19, 2007)

I have heard horror stories from people that sandblast sparkplugs -which was common in the old days when when the land was rural and stores were miles away. The blasting media can get lodged in the small space between the porcelan and the metal casing - and when your engine is running it comes loose and gets between the piston and cylinder and gouges everything up. The only media that I heard is safe for this purpose is Walnut shells that are ground up - BMW used them for a while when they were having trouble with carbon building up on the back of the intake valves - they could remove the intake manifold and blast the back of the valves while the engine was still together.

Spark plugs are cheap - engines are not. If you have an engine that is hard on plugs and worth keeping.....find out why it is burning so rich and get it fixed. If I have to clean a plug I use a wire brush to get the worst mess off and then use carb cleaner to blow it out - then a small piece of sandpaper to clean the tip of the electrodes.


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## rxe (Dec 19, 2007)

Brass wire brush, if they need doing at all.


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## wkpoor (Dec 19, 2007)

I'll agree to the economics of buying plugs vs the blaster but..... I don't own a blaster for just saw plugs. I probably have over 200 plugs in all the equipment around here and I certainly don't stock spares for all that stuff. As for Hokey.....Hmmmmm.... well we use the same process and media to blast the plugs in aircraft engines worth more than my house in some cases and we do it every 100 hrs. Seems to me a chainsaw motor ain't quite that critical in comparison. Its called pay attention to what you are doing. Inspect the plug carefully before installing even when they are new.


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## jhellwig (Dec 19, 2007)

Buy one, don't buy one. I don't care.


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## ray benson (Dec 19, 2007)

I have a glass blaster at home and had a big one at work. Used them on lawnmower plugs, car and truck plugs, chainsaws, weedwackers you name it. Just need to be very careful to remove all the glass beads.Blow them out and spray with electronic cleaner.Most guys won't take the time to do it. Anymore very few even do there own vehicle oil changes.


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## windthrown (Dec 19, 2007)

Plugs are what, about a buck or two each? I have mostly Stihls, which all take the same plugs. By the time you mess with cleaning and inspecting them and all, it is just not worth cleaning them. If they look good, I will keep them around as spares. Otherwise, I toss 'em and move on with life. 

That kind of chisel savings on cleaning and reusing plugs is about what my girlfriend wants here when I ask her to get premium gas for the chainsaws. She says that everyone else around here uses regular in their saws. I tell her that is why Jack can make a living down at the saw shop, all these people running regular gas in their saws. And half of them use ethonol gas to boot. I have to show her the Stihl manual at least twice a year (see? mid grade!). Then she wants to get mid-grade... so I have to explain about octane degrading in gas that sits in a can for a month. Then she wants to get less gas, more often. But being as the nearest station is 15 miles from here, that is not such a good idea. Its a downward spiral and I just wind up tossing her more money and say get the dang super gas already! 

There are places to save money and there are places not to. opcorn:


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## Dan Forsh (Dec 19, 2007)

Sprig said:


> Never have found a use for old ones except ta make your toolbox look fuller
> 
> 
> 
> Serge



Why do we do that?


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## Sprig (Dec 19, 2007)

Dan Forsh said:


> Why do we do that?


No idea, last time I clean out one of my tool boxes there was probably 5lbs of broken nuts and bolts, wtf, maybe my instinct not ta throw them on da floor and trip on them later, dunno, dunno, dunno, :bang:


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## wkpoor (Dec 19, 2007)

Some missed the point. 
I totally agree on just keeping spares. But the question was can it be done and what is the best way. I mostly replace myself. But many a time the little blaster has bailed me out of a jam at 6:00PM on Sunday or such. I would hate to inventory how many different types of plugs are in all the stuff at my place and figure what spares to keep. That would be a decent sized number. This $20.00 blaster has come in handy and does a good job if used right. Now if the only gas engine I own is my chainsaw.... then heck yeh, just buy plugs.


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## Lakeside53 (Dec 19, 2007)

Clean them? Nope... if they fire, just forget them. Mine look like crap on my saws when tuned for milling, but they work fine.


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## ShoerFast (Dec 19, 2007)

wkpoor said:


> Some missed the point.
> I totally agree on just keeping spares. But the question was can it be done and what is the best way. I mostly replace myself. But many a time the little blaster has bailed me out of a jam at 6:00PM on Sunday or such. I would hate to inventory how many different types of plugs are in all the stuff at my place and figure what spares to keep. That would be a decent sized number. This $20.00 blaster has come in handy and does a good job if used right. Now if the only gas engine I own is my chainsaw.... then heck yeh, just buy plugs.



I think the point some are trying to make, is plugs are a very small presantage of quality equipment's cost. 

The real story behind any type of abrasive cleaner, unless it's a routine clean, plugs don't crap out like that. 

When a plug goes bad, it is better then 9 times out of 10 that the spark is taking a short-cut throu were the cone of the porcelain attaches to the grounding base,,,,,, not sparking. Out of those 9 that miss-fired they got that way because gas washed conductive deposits into the porosity of the porcelain. Unless you burn them out, there in there. 

Even if you burn them out, some deposits stay in the porcelain and may not cause a cold start misfire, but will again quicker then it did the first time. 

So if your replacing a bad spark plug, chances are that you should also be looking at the starting procedure, or why it's flooding out.


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## OLY-JIM (Dec 19, 2007)

romeo said:


> I don't clean them with any more than a wire brush, if it fires its good, if it fails its trash. I have used a propane torch to clean fuel fowled plugs for the kids dirt bikes at the track. But that is only an "emergency-race-starts-in-5-minutes-technique".




Absolutely 100% re: wire brush!



Sprig; said:


> Yup, agree with you, a fine wire brush is all you need and make sure all the crud/debris is either blown out with air or washed with a bit o' fuel, check gap and plunk it back in if it looks good. Never have found a use for old ones except ta make your toolbox look fuller.



Once they're shot...they're excellent fishing / trott-line weights. Just ensure that they're well cleaned prior to initial use in order to avoid petroleum by product in the water while fishing...resulting in no bites! Really!


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## huskydave (Dec 19, 2007)

You sure can clean up an old plug. I use emery cloth and just rub it on both electrodes blow it off and regap. I used to run a lot of old snowmobiles and the mixture is 20:1 evey 200 miles or so your plug will foul and all you needed was some emery cloth and some time to keep it firing good. I try not to spend money on things that are not needed but thats just me. Plugs can last a lot longer if you clean them up when they get fouled. I don't think you can fix a burnt plug though if it gets too hot or too lean they are cooked.


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## buzz sawyer (Dec 19, 2007)

OLY-JIM said:


> Absolutely 100% re: wire brush!
> 
> 
> 
> Once they're shot...they're excellent fishing / trott-line weights. Just ensure that they're well cleaned prior to initial use in order to avoid petroleum by product in the water while fishing...resulting in no bites! Really!



Careful with the wire brush. Don't leave a shiney metal coating on the ceramic insulator or it can lead to shorting/misfire. If you have to clean it, open the gap and use a thin file on the electrodes, then reset the gap. That eliminates any abrasive from emery cloth or sandblasting. Just make sure the metal filings are removed - maybe hold the firing tip down while filing.


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## OLY-JIM (Dec 19, 2007)

buzz sawyer said:


> Careful with the wire brush. Don't leave a shiney metal coating on the ceramic insulator or it can lead to shorting/misfire. If you have to clean it, open the gap and use a thin file on the electrodes, then reset the gap. That eliminates any abrasive from emery cloth or sandblasting. Just make sure the metal filings are removed - maybe hold the firing tip down while filing.




Thankya...Thankya kindly!


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## Sprig (Dec 20, 2007)

OLY-JIM said:


> Absolutely 100% re: wire brush!
> *
> Once they're shot...they're excellent fishing / trott-line weights. Just ensure that they're well cleaned prior to initial use in order to avoid petroleum by product in the water while fishing...resulting in no bites! Really! *



Not sure what a 'trott-line' is but sounds kinda scary (jk), they're pretty heavy for spin casting but I do know people that use have used them for cod jigging, I much prefer a buzz-bomb on its own though for that. This does remind me that I haven't been fishing for a long time and have two 'new' rigs to try out, *sigh*, really do wish there was three of me sometimes 



Serge


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## OLY-JIM (Dec 20, 2007)

Sprig said:


> Not sure what a 'trott-line' is but sounds kinda scary (jk), they're pretty heavy for spin casting but I do know people that use have used them for cod jigging, I much prefer a buzz-bomb on its own though for that. This does remind me that I haven't been fishing for a long time and have two 'new' rigs to try out, *sigh*, really do wish there was three of me sometimes
> 
> 
> 
> Serge



It all depends on what kind of water your fishing and what equipment your using...? Trott line is just what we called them where I'm from...I'm sure you will figure it out?


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## Kogafortwo (Dec 20, 2007)

windthrown said:


> I usually just replace the plugs if they get fouled. They are cheap. Rarely happens though. I use NGK plugs in all my engines.



Buy *Bosch* plugs. That goes for everybody!

You will instantly gain 1000 rpm and 2 horsepower, and your chain will stay sharp forever.

Also please replace your Walbro carbs with *Bosch* fuel injection, and your chain brakes with a *Bosch* ABS brake system.

Sorry, I cannot reveal my employer to you. It's top secret.


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## JohnL (Dec 20, 2007)

Unless it is misfiring, why clean them? A light coat of carbon is pretty much normal, and doesn't effect performance. A heavy coat, too rich. Oil fouled, use a solvent, and dry it out.


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## RadChad (Nov 23, 2016)

Just put them in your wife's self cleaning oven and set it to clean!


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## bmwpowere36m3 (Nov 23, 2016)

garbage....


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## Amp4027 (Nov 24, 2016)

Carb&Choke cleaner sprayed onto it usually does the trick. Stainless Steel Wirebrush lightly used seems to do good too, but never knew about what buzz sawyer said, so I guess be careful with that method.


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## Marshy (Nov 24, 2016)

RadChad said:


> Just put them in your wife's self cleaning oven and set it to clean!


Welcome to the forum. Once in a while a member will revive an old thread out of the blue but this is impressive, nearly 10 yrs old!  Enjoy.


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## Lowhog (Nov 24, 2016)

The Wife's nail file and cook stove.


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## Franny K (Nov 24, 2016)

Post #20 may be the most informative from what I have done.

I have a copper bar with a hole threaded to the 14mm that most of my plugs use. There are smaller ones perhaps 10mm and 12mm. It also has a copper piece to protect the grounding electrode. Put the plug in and use a flame and burn out the insides as best as you can. It is possible to get a crack in the ceramic, the cool down probably should be a bit gentle. I have a feeling oxy propane could be a bit better than oxy acetylene.  Tiny flame. This seems to have a success rate somewhat better than 50%. It may not be all that repeatable, this plug in the picture was not saved but fortunately I had another that seemed sort of similar, a different brand so not sure if it was exact. I know there used to be cleaning little machines in mail order catalogs. Not sure how applicable that is to todays stuff, they used to de carbon engines blowing in oxygen.


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## 1Alpha1 (Nov 24, 2016)

Many years ago, when I was much younger, a neighborhood gas station closed it's doors. I knew the owner well, as he let me and many of my friends use his equipment to work on our dirt bikes. At one point, I ended up working there part-time, off the books, for pocket money.

Anyways, when he closed up, he was getting rid of a lot of his equipment, one piece being a spark plug cleaner. It was about the size of a 4-slice toaster. It could clean just about any size plug on the market. It used some kind of glass silica media to blast the plugs. It did a fine job.

The plug cleaner was mounted on a shelf in our old one-car garage. It got used countless times. Back then, money was a concern, and spark plugs didn't get thrown away all that often.

Not really sure what happened to it. I went into the military in 1974, and when I got out, my parents had moved to a different home, and the plug cleaner didn't make the move apparently. 

The coolest thing about that plug cleaner, is that it was made by The Champion Spark Plug Company.


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## Guido Salvage (Nov 24, 2016)

Marshy said:


> Welcome to the forum. Once in a while a member will revive an old thread out of the blue but this is impressive, nearly 10 yrs old!  Enjoy.



Necroposter...

I just use the wire wheel on my grinder.


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## RiverRat2 (Mar 16, 2017)

wkpoor said:


> There is cheap plug blaster on the market that works great. They look practically new when cleaned in one of these. Don't use sand, its a special plug blast material. Works with air pressure. I've had one for yrs. Yes plugs are cheap but it will keep you going when the stores are closed or too far away to justify the trip.


LOL I have one !!!!! cannot think of the name,,, Works great uses glass bead media and compressed air to drive it,,,, cleans them great!!! I was always told never use a wire brush



Guido Salvage said:


> Necroposter...
> 
> I just use the wire wheel on my grinder.


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## CR888 (Mar 17, 2017)

I won't sandblast spark plugs.... media can get stuck inside the plug and come out under operation. I just use a toothbrush & some gas or if it's really bad a wire brush.


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## Little Al (Mar 17, 2017)

Back in my apprentice days 1950/55 most plug manufactures had a blast type spark plug cleaners, & when I did my military service (RAF)they had blast type cleaning machines for the piston engined aircraft still in service. 24 plugs in Rolls Royce Merlin/Griffon, 48 in Napier Sabres, & 28 in the 14 cyl,& 36 in the 18 cyl Radials.There were guys doing this job full time, I am not sure of the process or the blast agent but the cleaned plugs when fitted never gave any problems so they must have had a way to remove all the sand or abrasive post cleaning.


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## RiverRat2 (Mar 17, 2017)

Yep an air nozzle gun with a fine outlet followed with a stiff brush gets if any left over blast media,,,,, works fine when you don't have time to drive 16 miles to auto parts and back to go get a new plug,,, never had a problem


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## ironman_gq (Mar 17, 2017)

Little Al said:


> Back in my apprentice days 1950/55 most plug manufactures had a blast type spark plug cleaners, & when I did my military service (RAF)they had blast type cleaning machines for the piston engined aircraft still in service. 24 plugs in Rolls Royce Merlin/Griffon, 48 in Napier Sabres, & 28 in the 14 cyl,& 36 in the 18 cyl Radials.There were guys doing this job full time, I am not sure of the process or the blast agent but the cleaned plugs when fitted never gave any problems so they must have had a way to remove all the sand or abrasive post cleaning.



A lot of the issues aside from oil and carbon with plug fouling back then was lead glazing which is hard and won't come off with a wire brush. Blasting was pretty much the only way to remove that.


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## Little Al (Mar 17, 2017)

Kogafortwo said:


> Buy *Bosch* plugs. That goes for everybody!
> 
> You will instantly gain 1000 rpm and 2 horsepower, and your chain will stay sharp forever.
> 
> ...


I can't comment on the fuel injection/ ABS chain brake, but the last box of 10 plugs of Bosch 6 were faulty 3 wouldn't spark at all, & the other 3 worked for between 5 & 15 mins a refund was issued straight away & despite asking the reason for the failures, no explanation was forth coming, this was some 3 years ago & we switched to Denso & to date have not had any problems at all. So sorry we won't/ don't use what is obviously your employers products, I must also add that we are a commercial logging set up & had had the odd failure before, but not by any means to that degree. I have no doubt others have suffered with other brands & each has his own favorite brand. We have used most if not all brands & Denso are the only completely trouble free brand.


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## Justsaws (Mar 17, 2017)

Lead oxide/ metal oxide glazing is why spark plug cleaners exist. Always wanted to know if the glaze that was manufactured on the insulator was lead based. Probably still is, Do not cook food with or rub your sparkplug on bare skin with vigorousness. Perverts. Stop putting them in your mouth, nose, ears and eyes. Without the addition of other materials it is a fragile glaze and is easily removed with glass. Little bit of silica, maybe some borax, feldspar whatever and it starts to get harder to remove, still stop rubbing it on your bare skin. Perverts.

Forgot heat, needs heat as well otherwise it is just a sandbox. A horrible horrible sandbox.


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## sbhooper (Mar 18, 2017)

Run Amsoil Saber Pro oil and quit worrying about fouling.


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