The 6 Best Catalytic Converter Cleaners of 2021

Jerry Wilson
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Over time, our vehicles accumulate a lot of gunk. From dirt, to grime to road debris, all of this dirt and grime can cause damage to your car and can cost you money.

Catalytic converters are especially vulnerable to these contaminants and they can become clogged with all of this gunk. As you drive, the cat converter does its job and is supposed to clean exhaust fumes to keep them from entering the air.

But if your cat converter becomes clogged, it will do a worse job of protecting the environment because it creates more pollution.

The best catalytic converter cleaners are going to get rid of this gunk quickly and painlessly. Even if you don’t know what your vehicle uses, you can always use the best convention cleaner to clean any converter on the road.

We put together this list to help you pick the best one for your needs.

Mr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. BottleBest OverallMr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. Bottle
CRC Guaranteed to Pass Emissions Test FormulaBudget PickCRC Guaranteed to Pass Emissions Test Formula
Cataclean 120007 Complete EngineUpgrade PickCataclean 120007 Complete Engine

1. Mr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. Bottle

Our rating: 9 / 10

Mr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. Bottle

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  • Kills emission deposits
  • Removes clogging from your system
  • Available in multiple sizes and quantities

The majority of vehicle owners fall for the “used car salesman” line of tricks and end up buying a clunker that pollutes massively. However, one way to cut back on tailpipe pollution is by making sure the catalytic converter is working correctly.

Cataclean is one of the best catalytic converters cleaners you can get in the market, and is ideal for smaller repair jobs. It’s available in a 5L bottle, which is enough to cover the Ford Raptor’s engine, as well as a range of other vehicles and industrial applications.

It dissolves fuel and exhaust deposits to enable the catalytic converter to reach its efficiency potential, and doesn’t destroy the converter. This ensures smooth engine performance.

2. Cataclean 120007 Complete Engine

Our rating: 7 / 10

Cataclean 120007 Complete Engine

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  • Fast acting formula
  • Cleans engine, fuel and exhaust system
  • Includes 473 ml bottle, one for every spec of dirt


  • Strong smell
  • A little pricey
  • Not for use with catalytic converters containing precious metals

Cataclean is an engine cleaner that cleans engine, fuel and exhaust system that comes with 473 ml of product. The product is great for your vehicle regardless of your automotive passion – whether you are a fanatic who needs to clean and maintain your truck each morning, or attend class every afternoon. It cleans engines by removing the deposits and contaminants that are caused by combustion and other contaminants. The cleaners are literally a godsend for reducing the risk of toxic fumes and also cancer. They are non-bleeding, non-evaporating, non-staining and solvent free.

For more information about the product, you can check out the official website or Amazon website.

The spray is an inexpensive engine cleaner that cleans your engine, fuel and exhaust system. It is environment and engine friendly and non-toxic. The cleaner comes with a power spray that dissolves and cleans the engine, deposits, dirt, grease, and other contaminants. It is approved by engine builders and hot rod enthusiasts. It is a non-flammable product, and free of many chemicals that may cause health problems such as cancer.

3. OXICAT – Oxygen Sensor & Catalytic Converter Cleaner

Our rating: 7 / 10

OXICAT - Oxygen Sensor & Catalytic Converter Cleaner

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  • Easy to use
  • Dissolves all kinds of buildup
  • Removes carbon buildup from sensors
  • Affordable price
  • Safe for the environment


  • Sticky and won’t spray well
  • Lacks pressure
  • Some reviewers complained of a foul smell
  • Hard to tell when it is full
  • The Organic Stain Remover From Mighty Paws This highly effective laundry product also works great for removing unsightly stains from carpets and upholstery! Containing only organic bio-friendly ingredients, Mighty Paws stain remover is safe to use in conjunction with just about any carpet cleaning method, hot or cold water extraction, steam cleaning, extractor cleaning, or any other method.

Thanks to its unique way of working, Mighty Paws Organic Stain Remover can be used to remove some very tricky and stubborn stain types from carpets. These include (but are not limited to) juice, coffee, paint, tar, vomit, wine, blood, food, red wine, rust, list goes on and on.

Unlike most conventional carpet stain removers that contain harsh chemicals and surfactants, Mighty Paws organic stain remover only contains natural and organic ingredients.

4. CRC Guaranteed to Pass Emissions Test Formula

Our rating: 7 / 10

CRC Guaranteed to Pass Emissions Test Formula

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  • Guaranteed to pass emission tests
  • Easy to use

Emission tests may be used for voluntary compliance or mandatory state, county, and city checks. CRC guarantees that this product will pass EPA-approved emission tests.

This formula is designed to clean out your entire system and guarantee to pass your state’s emission tests. If you don’t pass, they will buy back the unused portion. The formula is easy-to-use and makes cleaning your catalytic converter 101.

The four-step kit has the installation kit, in-line flushing trays, cleaner, and a PDF with instructions. Also included are an in-line flow meter and a kit for no-drain applications.

5. Solder-It

Our rating: 7 / 10


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  • Reasonably priced despite containing a superior design
  • Seals cat converters
  • Packaged in a special patented nozzle which enables users to clean inside the converter
  • Prevents emissions of unburned hydrocarbons into the atmosphere
  • Removes sludge and carbon deposits


  • Available in limited areas
  • Sold per retail outlets only
  • More pricey than similar products

For decades, Solder-It has been the long-term number one choice of catalytic converter cleaner in the market. Solder-It Catalytic Converter Cleaner is specially designed for RVs, Campers, SUV, Trucks, Vans, Cars, and Motorcycles The product ranks high in terms of safety, yet remains economical.

The product contains a unique spray nozzle, which results in a high quality spray control, designed to facilitate the effective use of this product.

A user friendly catalytic converter cleaner, it reduces burning of fuel in the engine, reduces smoke from the exhaust and purifies the exhaust gas for improved overall driving experience.

6. Hi-Gear HG3270s EZ Emissions Pass and Catalytic Converter Cleaner

Our rating: 7 / 10

Hi-Gear HG3270s EZ Emissions Pass and Catalytic Converter Cleaner

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  • Converts sludge into liquid to flow out through the exhaust
  • Lightweight and easy to apply
  • Safe for all emission controls devices
  • Can be used on all catalytic converters
  • Removes minor sludge and varnish
  • Purifies and cleans the exhaust system
  • Contains Purotect

The Hi-Gear HG3270s EZ Emissions Pass and Catalytic Converter Cleaner is a proven brand that’s been trusted by mechanics for many years. As an automotive technician for the past decade, I’ve seen firsthand that Hi-Gear delivers high-quality products, and this is one of them.

The Hi-Gear HG3270s converts sludge and varnish into liquid so it can easily flow into the exhaust system and be flushed away. It also contains Purotect, a chemical that helps clean the air of dangerous particles.

This cleaner is compatible with EZ emissions passes, and it comes in a convenient trigger spray bottle. It's also safe to use on all catalytic converters, so it can be used on all cars.

Frequently Asked Questions (FAQ)

What is the best catalytic converter cleaner on the market?

There are countless brands of catalytic converter cleaners on the market. However, common trends include Oxygen Bleach or Hemi-Cleaner. Although I don’t prefer these brands, I will acknowledge that they are well-known, widely-used, and can do the job. Also, they’re easily available along with plenty of online reviews, which are very helpful.

Aside from Oxygen Bleach and Hemi-Cleaner, Cataclean is a great, very reliable brand of catalytic converter cleaner. It’s well reviewed by users and one of the best on the market.

Do catalytic converter cleaners actually work?

Yes, and it is recommended to use a cleaner every month or two to prevent build-up.

Catalytic converters are vital parts of your car that help reduce tailpipe emissions (especially dangerous Nitrous Oxide). Most of these converters are made of precious metals and are very delicate. They are also expensive to replace so it's in your best interest to keep them in good condition.

Although they are an important part of your car, the converter is largely out of sight and out of mind for most people. You can wait until your car stops running before you do anything about the state of your converter, but you should avoid this. Many states have laws about the use of a cleaner in your car, so make sure you check the regulations where you live.

Is there a fuel additive that will help clean the catalytic converter?

Important note: While you can certainly purchase an additive to help clean the converter better, there is no fuel additive on the market that will be able to remove carbon deposits from the inside of the converter itself. The only way to effectively clean the inside of the converter is to have it professionally flushed or replaced. Unless the converter is physically damaged, the best you can do is to help the functioning of your converter, which is exactly what additives purport to do.

Since the technology behind engine additives is confusing (and really hard to explain), we’ve written an article that goes through the science of a catalytic converter. In it, we discuss the way additives actually work and what you can expect from them. However, feel free to read on for an overview of the issue below.

Now, for the science:

Is a high flow catalytic converter worth it?

Here's a brief, but simple explanation of flow and efficiency:

The flow of a catalytic converter refers to how much exhaust it can process at once.

The efficiency of a catalytic converter refers to how much exhaust it can process and prevent from going into the environment.

Put it all together and you get how effective a catalytic converter is overall. They amount of exhaust is important, but it can be mitigated without removing all of it by making it so the converted exhaust is as clean as possible.


The catalytic converter is a standard feature that has been found in vehicles since the early 1990s. It is part of the vehicle’s pollution reduction system, and it not only helps protect the environment, but also keeps the vehicle from over-polluting the air. If the converter’s efficiency decreases, so too does the effectiveness of the engine’s pollution reduction system.

Our Recommendation

Mr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. BottleBest OverallMr Gasket 120009 Cataclean Fuel And Exhaust System Cleaner 5 L. Bottle
CRC Guaranteed to Pass Emissions Test FormulaBudget PickCRC Guaranteed to Pass Emissions Test Formula
Cataclean 120007 Complete EngineUpgrade PickCataclean 120007 Complete Engine