6 Best Catalytic Converter Cleaners of 2021

by Joshua Thomas

Catalytic converters cut down the amount of pollution that's produced by a car's internal combustion engine by trapping it. Hence, they get clogged with carbon buildup over time, resulting in a less efficient filtering of your car's exhaust gases.

With the best catalytic converter cleaner, you can easily and quickly return your catalytic converter into good working condition.

These specially formulated cleaning agents help to get rid of the grime and dirt build up in the catalytic converter, and in the process also help to unclog it. But, you need a good cleaner to get the most effective cleanup.

Here we provide a list of the best catalytic converter cleaners and show you how to choose the right one.

Table of Contents

Summary of 6 best Catalytic Converter Cleaners

Mr. Gasket Cataclean Catalytic Converter Cleaner
Mr. Gasket Cataclean Catalytic Converter Cleaner
1. Cataclean 120007 (Best Overall)
  • Top brand product with proven results
  • Will not alter fuel composition
  • 50% lower total hydrocarbon emissions
  • Safe for most kinds of vehicles
CRC 05063 Guaranteed To Pass Emissions Test Catalytic Converter Cleaner
CRC 05063 Guaranteed To Pass Emissions Test Catalytic Converter Cleaner
2. CRC 05063 (Most Powerful Detergents)
  • Powerful detergent additives
  • Guaranteed to pass emission tests
  • Works with all fuel types
  • Significant emission decrease
Autoprofi Oxicat Oxygen Sensor & Catalytic Converter Cleaner
Autoprofi Oxicat Oxygen Sensor & Catalytic Converter Cleaner
3. Autoprofi Oxicat (Ideal for Gas, Diesel & Hybrid Vehicles)
  • Ideal for most fuel types
  • Cleans both catalytic converter and oxygen sensor
  • TUV certified to be safe and effective
  • Boosts overall engine performance
Solder-It CAT-1 Catalytic Converter Cleaner
Solder-It CAT-1 Catalytic Converter Cleaner
4. Solder-It CAT-1 (Best Budget)
  • Relatively more affordable
  • Removes rotten egg odor
  • Also cleans oxygen sensor
  • Can be helpful for passing emission tests
  • Longer time between tune-ups
Mr Gasket 120009
Mr Gasket 120009
5. Mr Gasket 120009 (Industrial Use Cleaner)
  • Great for industrial use
  • Works for gasoline, diesel and hybrid vehicles
  • Also cleans oxygen sensors
  • Up to 60% emission reduction
Hi-Gear HG3270s
Hi-Gear HG3270s
6. Hi-Gear HG3270s (Maximum Fuel Efficiency)
  • Increases fuel efficiency
  • Removes and prevents rotten egg smell
  • Helps you pass emission test
  • Restores lost horsepower

1. Cataclean 120007 - Best Overall

Mr. Gasket Cataclean Catalytic Converter Cleaner
Mr. Gasket Cataclean Catalytic Converter Cleaner

Cataclean has been making vehicles accessories for more than two decades now, and they are one of the most reputable brands in the market. This and highly effective formulation of this product are what make it our best overall.

The patented formula breaks away carbon deposits along its path, reducing their buildup and cutting down your car's emission levels by up to 50%. And it will restore your vehicle's catalytic converter, the oxygen sensors, cylinder heads, and injectors.

This product will work for most vehicles as it is effective for both gasoline and diesel engines and also for hybrids. Motorists will also love that it does not alter the fuel in any way, and so the vehicle maintains peak performance.

Usage is simple. Just open the bottle and empty it into your car's partly filled tank and that's it. Repeat in a few months to keep your car well maintained.

Cataclean is legal in all US 50 states. It complies with federal low sulfur content regulations, as well as the Volatile Organic Compound (VOC) regulations.

The only shortcoming is that it does not work for 2 stroke engines. However, for most motorists, this is hardly even an issue.


  • Reduces emissions up to 50%
  • Works safely with both gas and diesel engines
  • Improves overall vehicle performance
  • Legal in all 50 states
  • Easy to use


  • It's not for use in 2-stroke engines

2. CRC 05063 - Most Powerful Detergents

CRC 05063 Guaranteed To Pass Emissions Test Catalytic Converter Cleaner
CRC 05063 Guaranteed To Pass Emissions Test Catalytic Converter Cleaner

CRC boasts that you'll either pass your emissions test with this cleaner or they'll give you double your money back. Now that's a bold statement, especially coming from a reputable company like CRC.

But what truly makes this an amazing catalytic converter cleaner, is the inclusion of some powerful detergent additives that ensure efficient cleanup of your entire fuel system.

CRC recommends that you use it every 3,000 miles to keep your vehicle's fuel economy and emission levels healthy. It will work with all kinds of ethanol and gasoline blended fuels.

With this top-rated catalytic converter cleaner, you will also get significant reduction in emissions and an increase in overall performance.

CRC makes no mention of its suitability for diesel engines, which for some users might be a concern. But, if you use gasoline, this is not an issue for you.


  • Includes powerful detergent additives that act fast
  • Guaranteed to help you pass your emissions test
  • Works with all kinds of ethanol and gasoline blended fuels
  • Quickly restores your car's fuel system to like-new
  • Lowers emissions significantly


  • Not for diesel engines

3. Autoprofi Oxicat - Ideal for Gas, Diesel & Hybrid Vehicles

Autoprofi Oxicat Oxygen Sensor & Catalytic Converter Cleaner
Autoprofi Oxicat Oxygen Sensor & Catalytic Converter Cleaner

The Autoprofi Oxicat cleaner is safe for use in all kinds of fuel, including gasoline, diesel, and different hybrid vehicles and fuel mixes. This means, it will work for you regardless of the vehicle you drive.

It is made in Germany under the Pro-Tec and Autoprofi brands, which promises both high quality and reliable cleanse. And the fact that it is certified by the German TUV quality and certification agency shows that it achieves this.

This catalytic converter cleaner fluid was developed as a high-performance cleaner that can effectively remove carbon deposits, soot, and all kinds of dirt from your vehicle's fuel and exhaust systems.

Additionally, Oxicat promises to keep your vehicle in top overall form with regular use. Regular use here translates to 3-5 uses per year.

Although there seems to be relatively less product in the bottle, and this is more so when compared to others on our list, there is still enough to ensure effective catalytic converter cleanup.


  • Works with all kinds of fuels
  • Gets rid of all deposits
  • Restores engine performance
  • Protects the system against heavy dirt
  • High-quality and reliable German technology


  • Little product in the bottle

4. Solder-It CAT-1 - Best Budget Catalytic Converter Cleaner

Solder-It CAT-1 Catalytic Converter Cleaner
Solder-It CAT-1 Catalytic Converter Cleaner

Solder-It's CAT-1 catalytic converter cleaner is a more affordable, but still highly effective solution for cleaning your car's fuel and exhaust system.

Many motorists seem to love most about it because it is more effective at getting rid of the "rotten egg" smell, which is something even more expensive might not be able to do.

It's designed exclusively for gas engines and will clean all types of catalytic converters, including the monolithic and the pelleted types. It's also safe for use with the oxygen sensor and helps to clean it as well.

This catalytic converter cleaner can be helpful for passing emission tests. And with it on your vehicle, you also get more time between tune ups, which saves you cash.

Although you may need to use more than one bottle of this catalytic converter cleaner, this should not be an issue given the more affordable price tag.


  • More affordable
  • Also helps to clean oxygen sensor
  • Gets rid of rotten egg smell
  • Works on both monolithic and pelleted converters
  • Allows for more time between tune-ups


  • You may need more than one bottle

5. Mr Gasket 120009 - Industrial Use Cleaner

Mr Gasket 120009
Mr Gasket 120009

Mr Gasket 120009 is formulated for industrial use, and it will be the perfect catalytic converter for you if you have a fleet of work vehicles and for trucks.

This formulation is effective at cleaning catalytic converters, oxygen sensor and the exhaust system. Also, the catalytic converter cleaner will be effective on diesel, gasoline and hybrid vehicles.

When using this product, you will get up to 60% reduction in the emission, and it is also highly effective at dealing with carbon buildups.

This product is quite potent and can damage paint, but with a little precaution, there is nothing to worry about. Also, since it is an industrial grade cleaner, you can expect it to work even for 2 stroke engines, but it does not. However, this is also still not a deal breaker.


  • Special formulation for industrial use
  • Up to 60% emission reduction
  • Effective at cleaning oxygen sensors
  • Significant carbon build-un reduction
  • Works for different kinds of vehicles


  • Can damage paint
  • Will not work with 2 stroke engines

6. Hi-Gear HG3270s - Maximum Fuel Efficiency

Hi-Gear HG3270s
Hi-Gear HG3270s

With this catalytic converter cleaner, you will clean up the system and get a decent increase in fuel efficiency, which means it will save you cash.

This product will also be effective at cleaning the combustion chamber, pistons, valves, and injectors, which boost vehicles overall performance.

And you can expect to get back lost acceleration and horsepower, and hard starts should also be fixed.

With this product, you will also get rid of rotten egg smell, and it can be very useful at helping you pass emission tests since it lowers emission of CO2 and toxic fumes greatly.

While for some vehicles one bottle is enough, for many others you will need several to remove heavy build-ups. But, given the smaller price tag, this should not be a problem.


  • Significant increase in fuel efficiency
  • Gets rid of rotten egg smell
  • Will help pass emission tests
  • Removes carbon deposits effectively
  • Restores horsepower and acceleration


  • One bottle is hardly enough

How Catalytic Converter Cleaners Work

How Catalytic Converter Cleaners Work
How Catalytic Converter Cleaners Work

A catalytic converter cleaner works with chemical reactions to remove the build-up in a car's exhaust system. This includes the cylinders, fuel injectors, and other parts of the exhaust.

Catalytic converter cleaners are solvents, which when added to fuel will break down the carbon deposits it mixes with as it flows through a car's combustion and exhaust system.

By simply coming in contact with these hydrocarbon particles, the cleaner breaks down their molecular structure, making it easier for them to get transported out of the exhaust system. This then improves the car's overall performance.

Benefits of Catalytic Converter Cleaner Additives

There are four main benefits of these cleaners though, and they're as follows:

1. Improves Engine Performance

This is one major benefit of using a catalytic converter cleaner. Improperly combusted hydrocarbon particles tend to stick to some engines parts and disrupt their proper functioning, thereby reducing the car's efficiency.

A catalytic converter helps clean the fuel injection system, which produces more power with less fuel. It also helps clean the cylinders and cut down on friction, improving overall power.

Any object in the pathway of exhaust gases reduces the engine's performance. As the cleaner cleans out carbon deposits in the converter, therefore, there is less blockage and a corresponding improvement in the engine's performance.

2. Lowers Emission Levels

A French scientist invented the catalytic converter in the early 20th century to cut down on the level of harmful gases produced car engines. These gases are harmful to the environment and to humans as well.

Reducing the emission level from cars has always been a subject of ongoing debate, with early converters only turning hydrocarbons and Carbon Monoxide into the less harmful Carbon Dioxide. Newer cars since the 1980s additionally include a third converter to convert Nitrogen oxides.

Using a catalytic converter cleaner helps to cut the emission levels of your vehicle to acceptable levels, enabling you to pass the test and additionally be nice to the environment.

3. Saves You Money

Having a clean engine and exhaust system saves you money in two ways. The first way is that you don't have to spend plenty of money to change your vehicle's catalytic converter because you can clean it very easily.

The second way it saves you money is in lower maintenance and fuel costs. This comes as a result of the car engine's improved efficiency, producing more power with less fuel.

4. Gets Rid of that Rotten Egg Smell

Any vehicle that's been running rich for a while will develop a rotten egg smell coming from its exhaust pipe, once carbon deposits have caused enough damage in the converter.

When cleaner works on your car's combustion and exhaust system, the smell also disappears.

How to Buy the Best Catalytic Converter Cleaner

Catalytic Converter Cleaner Buying Guide
Catalytic Converter Cleaner Buying Guide

There are a few things to check when choosing a catalytic converter, and they include the following

1. Compatibility

While many auto catalytic converter cleaners will be compatible with a range of engines, including 2-stroke and 4-stroke, or diesel and gasoline engines, some cleaners could turn out incompatible with certain engines.

It's left for you to know what kind of engine or system that you're about to clean and to take a quick glance on the cleaner's manufacturer instructions, to make sure that it's compatible.

But, something that can clean diesel, gasoline and hybrid engines like Autoprofi Oxicatis always a better buy.

2. Eco-friendly

A catalytic converter cleaner is a bottle filled with chemicals, so you need to know how safe it is to use in your car, as well as how safe it is for the environment if you're Eco-friendly.

You can confirm that the cleaner meets the necessary regulations like the VOC (Volatile Organic Compound) and OTC regulations, or others like the low-sulfur content requirements.

3. Capacity

You should keep in mind that a catalytic converter cleaning routine is not a one-off event, but is rather something you need to do from time to time.

So you may want to consider any packages that offer you a volume discount so you can save some money in the long run.

Some options like Mr Gasket 120009 are design for larger capacity vehicles like truck and for industrial use that will require more product for maximum effectiveness.

How to Use a Catalytic Converter Cleaner

How To Use A Catalytic Converter Cleaner
How To Use A Catalytic Converter Cleaner

Following is a simple 7-step guide to getting the best from your catalytic converter cleaner of choice.

Step 1: Check your Spark Plugs

You might wonder what spark plugs have to do with cleaning your vehicle's catalytic converter. The truth though, is that excessive carbon buildup on your converter is probably a sign that your vehicle is running rich.

By "running rich", the fuel and air mixture is either not right, or one of your spark plugs isn't sparking correctly. It's a good idea to change your plugs from time to time, especially if you don't remember the last time you changed them.

Having good spark plugs helps to lower the rate of carbon build up on your catalytic converter by burning all the available fuel completely. You'll need to check your vehicle's manual to know the type and amount of plugs to buy.

Step 2: Add the Cleaner

Once you've dealt with your plugs and everything is okay, it's now time to empty the contents of the cleaner that you bought, into your vehicle's gas tank. Simply open the tank, open the bottle, and then empty it inside.

Always remember to read the instructions before using it. So, if your specific cleaner comes with any specific instructions, then make sure you stick to its instructions.

Step 3: Fill the Tank

You should now fill your vehicle's tank until it's full or about 10 gallons. However, you can also check the recommended fuel to catalytic converter cleaner mixing ratio to determine how much fuel you need.

Step 4: Drive Around till Empty

It's recommended that you drive around for at least 50 miles straight after the application to get the best results from the cleaning process. Ideally, you should drive the car until the tank is empty.

Step 5: Check Engine Light

Your car's check engine light should go off by now, else, feel free to repeat the process. If your vehicle alerted you to the catalytic cleaner's issue using error codes, now will be the time to clear these codes.

Since cars are different, you may need to consult your vehicle owner's manual to see instructions on clearing the codes, or it could be automatic.

Read More : How to Reset Check Engine Light

Step 6: Refill your Tank & That's It!

Refill your tank and carry on with your day-to-day activities, or go and test your car's emission levels. The cleanse should definitely be over by now.

Remember to cleanse your car again from time to time. The exact time-frame though depends on how often you use the vehicle. Once a year is okay for cars you seldom use, with up to 3-4 cleaning sessions per year for cars you use daily.

Read More : How to Clean Catalytic Converter

Frequently asked questions

Do Catalytic Converter Cleaners Actually Work?

A: Yes, provided you choose a good model, it should be effective at not only cleaning your catalytic converter but also other things like fuel system, pistons and injectors.

Read More: The Best Fuel Injector Cleaner

Can a Clogged Catalytic Converter be Cleaned by Catalytic Converter Cleaner?

A: Yes. Most of the clogging often results from carbon build. Hence, the fact that these products are meant to remove this build up means it can clean a clogged catalytic converter. However, some severe clogs are beyond the abilities of the cleaner and might necessitate a catalytic converter change.

How Often Should I Use Catalytic Converter Cleaner?

A: It depends on various factors like the fuel type you use and the potency of the product. That said, many experts recommend using these product 3 to 4 times a year, or after every 4,000 miles.

Is it Safe to Use Catalytic Converter Cleaner?

A: Yes, catalytic converter cleans are generally safe for all vehicle makes and models. However, it is important to make sure you buy a product that is compatible with the specific fuel type that your vehicle uses to avoid problems.



Effectiveness should always be at the top of your mind when choosing then best catalytic converter cleaner. The good news is that every option on our review is highly effective.

But, the Cataclean 120007 seems to have an edge over the others in different aspects from emission reduction to ease of use, and it is hence our best overall and top recommendation.

For motorists looking for something effective that also offers good value for money and removes the rotten egg smell effectively, the inexpensive Solder-It CAT-1 is perfect.

About Joshua Thomas

Joshua Thomas just simply loves cars and willing to work on them whenever there's chance... sometimes for free.

He started CarCareTotal back in 2017 from the advices of total strangers who witnessed his amazing skills in car repairs here and there.

His goal with this creation is to help car owners better learn how to maintain and repair their cars; as such, the site would cover alot of areas: troubleshooting, product recommendations, tips & tricks.

Joshua received Bachelor of Science in Mechanical Engineering at San Diego State University.

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