How To Clean Your Catalytic Converter

In this article, we will look at how to clean your catalytic converter using the best pour and go products, like Duralube, Cataclean, and if lacquer thinner still works.

Did your check engine light come on? Do you smell a rotten egg smell emanating from your car? Did your car fail its emission test? Did you find a P0420 error code when you scanned your car? These are all good indicators that you may have carbon buildup with your catalytic converter.

By Maurice Rodriguez
November 1, 2021

Diagnosing and troubleshooting an error code like P0420: Catalyst System Efficiency Below Threshold or P0421: Warm Up Catalyst Efficiency Below Threshold can be difficult to pinpoint but several parts could be causing this issue to occur. Getting a check engine error code can seem difficult to interpret and even more daunting to fix. But, we will look

How does a catalytic converter work?

Catalytic converters work just like a filter that uses platinum, palladium, and rhodium to create a chemical reaction where carbon emissions are trapped in the mesh of the catalytic converters and clean the exhaust to release fewer greenhouse gases. The illustration below is the entire process from beginning to end.

Vector illustration of the Car Catalytic Converter – cross-section.

5 Symptoms your catalytic converter needs to be cleaned

We have created an easy chart to see if you have all the telltale signs that your catalytic converter has too much carbon buildup and needs to be cleaned.

How to Clean your Catalytic Converter

Damaged Catalytic Converter.

Material List

  • ODBII Scanner
  • Catalytic Cleaner – For a full review of the best cleaners on the market click on this link

How-to Steps

Step 1. THIS IS THE MOST IMPORTANT STEP. DO NOT SKIP! It is recommended by most catalytic converter cleaner manufacturers to start with a ¼ tank of gas or 4 gallons of fuel. Obviously, you will have to adjust for larger or smaller tanks to get to the 4-gallon mark. Specifically, for Cataclean the ratio is 4 gallons to one bottle.

Step 2. Remove the seal on the bottle and pour the entire contents of the bottle into your gas tank.

Step 3. Drive your car for approximately 15 minutes to give the product a chance to clean the carbon buildup on your cats. If you have a freeway on-ramp nearby, accelerate briskly to give the cleaner maximum airflow to remove any trapped carbon.

Step. 4. Once you have driven your car sufficiently, fill the tank.

Step 5. After 50 miles of driving, you can clear any error codes using a handheld scanner or at any auto parts store. If the error code doesn’t come back, then you are done. If the check engine light comes back, you may need more extensive diagnosing done by a certified. professional. It’s possible that your O2 sensors are at fault or your catalytic converter is too far gone to clean or service.

Top 5 Catalytic Converter Cleaner

#1 Pick – CataClean

In 1995 Cataclean Global in the UK began developing a patented pour and go formula for cleaning fuel and exhaust systems. Their solution was Cataclean Petrol, a cleaner that can reduce emissions by 60%, improve MPG, and protect and maintain your catalytic converter.


  • Reduce emissions by 60%
  • Improve MPG’s
  • Restore engine performance
  • Protect and Maintain your catalytic converter


  • None we could find

#2 Pick – Dura Lube

Duralube has been in business since 1986 and has been manufacturing fuel additives for gas and diesel engines. They have introduced Dura Lube’s Severe Catalytic & Exhaust treatment a pour and go solution in a bottle. As the name implies you can pour into your fuel tank and help pass an emissions test, can treat P0420 error codes, and improve overall engine performance.


  • Help pass emissions test
  • Can treat P0420 error codes
  • Improve engine performance


  • None we could find

#3 Pick – CRC Guaranteed to Pass Emissions Test Formula

CRC Guaranteed to Pass Emissions Test Formula is a very interesting product. Its claim to fame is if you are trying to get your car to pass the emission test it uses powerful detergents to remove deposits in your fuel system and carbon buildup in your catalytic converter. CRC’s guarantee stipulates that if you use a treatment of their formula and have driven 3,000 miles (and there is no underlying damage to the cats) and your car fails the emission test or inspection they will give you “double your money back.” That should give the sense that they stand behind their product.


  • Double your money-back guarantee if you fail your emissions test
  • Reduces harmful emissions
  • Removes harmful deposits in your fuel system
  • Cleans your catalytic converters


  • None we could find

#4 Pick – OXICAT Oxygen Sensor

Oxicat Oxygen Sensor and Catalytic Converter Cleaner is manufactured in Germany by the BlueChemGroup since 1988. Oxicat can remove carbon deposits from the entire exhaust system, EGR valve, oxygen sensors, and especially the catalytic converter. The manufacturer also recommends users use it when the gas tank is ¼ full and drive until almost empty.


  • Remove carbon deposits
  • Cleans the entire exhaust system including the catalytic converters
  • Cleans O2 and EGR valves


  • No guarantee

#5 Pick – Solder-It CAT-1

Solder-IT is based out of Pleasantville, NY, and manufactures a catalytic converter cleaner that also deodorizes and eliminates offensive odors. Solder-IT can help pass emissions tests as well. It is also a pour-and-go formula that is poured directly into the gas tank. The manufacturer recommends driving until nearly empty before refilling with fuel.


  • Cleans and Deodorizes catalytic converter
  • Eliminates foul ‘rotten egg’ smells
  • Helps pass emissions test


  • No guarantee

Boost-Up – We do not recommend

Boost-Up Vehicle Engine Catalytic Converter Cleaner is another pour and go cat cleaner but we could not find any information on who makes it and if they are a reputable company. We found this product being sold by lots of Chinese distributors so that may be the answer. I’m not sure I would trust a product that doesn’t openly share how, or where it is manufactured. I would pass on putting this product in my cars.


  • Claims to remove carbon deposits


  • No information on who manufactures this product
  • Mostly Chinese distributors
  • Very skeptical trying this product on my vehicles without getting more information on the product and company first
Adding lacquer thinner to fuel tank. Does it really work?

DIY – Does Lacquer Thinner work on your Catalytic Converter?

This is a controversial topic that has been discussed widely on the internet and among most mechanics. Some believe that putting lacquer thinner will work just as well as commercially available catalytic converter cleaners. Below we have to well know YouTube mechanics discuss the merits of using lacquer thinner.

Scotty Kilmer claims that he has been using 100% lacquer thinner in his vehicles and after a gallon of lacquer thinner and driving 15 minutes a P0420 error code can be cleared to never return.

Scotty endorses lacquer thinner and claims it works.

Eric The Mechanic Guy did his own testing and found that there was no noticeable difference when he used a quart of lacquer thinner on his own Subaru with clogged catalytic converters.

Eric has his doubts. We do too.

Now, my theory is that while lacquer thinner may not harm your fuel system and catalytic converters. You run the risk of not getting the ratio of fuel to lacquer correctly to be of any benefit. Plus, as Eric the Car Guy stated lacquer thinner is not one chemical and is a mixture of chemicals. It stands to reason Scotty’s blend is not the same as the of the shelf stuff you find at Home Depot.

I think there are too many variables (fuel/lacquer ratio, variety in lacquer blends) to know how to properly administer the lacquer to be effective enough to clean your fuel system and catalytic converters.

That’s why I would stick to commercial cleaners like Cataclean and DuraLube because the manufacturer has already determined the correct ratio and blend to get the job done. No guesswork. To me, that saves me time and headaches in the long run. I would rather get the job done right the first time around.


  • Inexpensive
  • Usually readily available
  • Doesn’t appear to hurt your fuel system or cats


  • Might not work the first time
  • Difficult to get the fuel to lacquer ratio right
  • Not all lacquer thinners are created equally
  • Too much guesswork

Pricing Chart – Where Do I Buy Catalytic Converter Cleaner?

We did the research so you don’t have to. Find the best price around on the internet below.

AutozoneAdvanced Auto PartsWalmartO'ReillyAmazon



Buy Now

Buy Now

Buy Now

Buy Now

Buy Now



Buy Now

Buy Now

Buy Now

Buy Now

CRC Guaranteted to Pass


Buy Now

Buy Now

Buy Now

Buy Now

Buy Now

OXICAT Oxygen Sensor


Buy Now

Buy Now

CAT -1


Buy Now

Buy Now


Does catalytic converter cleaner really work?

Depends. If you have no physical damage to your catalytic converters and your O2 sensors are functioning and your catalytic converter is just clogged from carbon build-up, then yes catalytic converter cleaners do work.

What is the best thing to clean a catalytic converter?

While lacquer thinner ‘may’ clean out your catalytic converters we recommend that you pick from our top 5 picks list for a commercially available product that is purposefully formulated to clean out your fuel systems and catalytic converters – like Cataclean or Duralube.

Can a clogged catalytic converter be cleaned?

Yes. There are several products like Cataclean and Duralube that will clean out your fuel system and catalytic converters and potentially help you pass emission tests and clear error codes like P0420.

Can I clean my catalytic converter myself?

Yes. Most commercial products like Cataclean and Duralube are ‘pour and go’ formula meant to be poured into the gas tank and done. Easy for anyone to do.


We hope you have learned everything you need to know about catalytic converters, how to troubleshoot them, common error codes, and providing some insight into lacquer thinner as a catalytic converter cleaner.

After all, is said and done we still stand behind our recommendation that Cataclean, Duralube, or CRC are your best top 3 picks to resolve any clogged catalytic converter issues you may have.

We are all things cars.

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