October 05, 2022

PCB cleaning can be more challenging than it sounds. It's important to understand what needs to be cleaned in order to determine how to clean the PCB. Are you cleaning flux residues, or machining oils or fingerprints. Is the PCB going to be conformally coated after cleaning? Does cleanliness testing need to be performed and also what are the volumes of PCB’s that need to be cleaned. We've put together this guide to help make cleaning your PCBs as easy as possible. We cover everything from what supplies you'll need to how to actually clean the boards.

PCBs are in every device in use today and some need to go through a cleaning process before being completed and many consumer devices may not need to have the PCB’s cleaned after assembly.

What is PCB Cleaning?

PCB cleaning is a process of removing harmful chemicals, soils and flux residues from PCBs. PCBs can become contaminated with a variety of substances, including flux, oils, grease, dust, and other particulates. Cleaning can be done using solvents or water-based chemistry.

There are a number of different types of cleaners available on the market and each one is designed for a specific purpose. You'll need to find a solution that is specifically designed for cleaning PCBs. Equipment-assisted PCB cleaning can be done using spray-type systems that spray a mix of chemistry that is designed to remove the specific soils and water or just a solvent that can be used in full concentration to remove those same soils.

What Do I Need to Clean My PCB?

There are a few things that you need in order to clean PCBs effectively. These include:

1. Manual or Low volume circuit board cleaning

PCB cleaning can be done manually, Manual PCB cleaning is typically done by using benchtop spray cans or dipping in solvents to clean the soils Spray cans of flux remover or other cleaning chemistry should be matched to the specific flux types that need to be cleaned. This is only for low volume, occasional use and spot cleaning.

2. Mid-volume PCB cleaner

Batch flux cleaners can clean medium volumes of PCB’s - based on PCB size they can clean from 15 - 50 (depending on size) PCB’s at a time in a batch cleaner and typical cleaning cycle is 30 - 45 minutes. This type of system does washing with a mix of DI water and chemistry using a high impact spray-in-air process inside the chamber, then rinses off the flux residue and wash solution using the spray nozzles and fresh DI water and then finally drys the PCB’s using convection blowers and heaters. Typical batch cleaners have “recipes” that can be set depending on the type of flux to be removed, the amount of flux on the PCB’s and the size or number of PCB’s to clean. Recipes can control wash time, number of rinses and dry time. These systems can also offer PCB serial # tracking using bar code reading… the types of PCB’s that need to be cleaned are generally of high value and tracking and process control is an important feature for long term product reliability.

3. High volume PCB cleaner

For higher volumes of PCB’s to clean an in-line automated flux cleaner is recommended. This cleaning method is high speed and automatically cleans, rinses and drys the PCB’s. These systems are in use by the largest PCB manufacturers that need to clean their boards. The military, security and defense industries generally still require flux cleaning. This type of equipment has high initial cost and has high running costs due to use of water and chemistry and power. This is also another piece of process equipment to purchase and maintain. That is why most high volume, consumer-oriented electronics has elin=minated the need to clean the flux residues.

4. Validation

How do you know if the PCB’s are actually clean after going through which ever process you chose to apply? The only way to validate that the boards are clean is to test using an Ionic Contamination Tester… this is checking to see if the ionic contaminants have been removed from the PCB’s as a result of the cleaning process. There are specifications that will determine if the cleaning process you have employed has met the criteria… if you do not measure you can not improve. Measurement is the only way to validate your process.

5. Cleaning Requirements

There is a shift away from the requirement for PCB’s to have flux residues removed due to the use of no-clean fluxes (which might be better described as low residue fluxes) as the small amount of residue can remain on the PCB and not cause any adverse effects to use of the final product. Most consumer electronics PCB’s do not need to be cleaned as the flux residue remaining on the PCB’s are not harmful to the long term use of the product. Some applications that may require the PCB’s to be conformally coated may still require cleaning to remove contaminants that could prevent the coating to adhere properly.

Other Cleaning Myths:

  1. Why do we need to clean “No Clean” flux residues? No clean flux is the most popular flux used for PCB assembly as cleaning is not generally required but, that does not mean there is no flux residue remaining… that just means that the residue is not harmful to the operation of the final product. And not cleaning this residue also means that other contaminants that are on the PCB will also not be cleaned off.

  2. When using a “water soluble” flux is only water required to clean off the flux residue? While the flux residues might generally be able to be washed off in warm DI water, not all of the residues on the PCB will be water washable and some residues and soils on the PCB will be hydrophobic and therefore not cleaned with just water. They will need some chemistry and spray action.

  3. Are solvents or water-based chemistry more commonly used when cleaning PCB’s of flux residues? Water based chemistry is most common as they are easier to work with and more environmentally friendly. Solvents are flammable and are more likely to be regulated as well as not environmentally friendly. The disposal of solvents can be very expensive while water based chemistry does not need to be disposed of through hazardous chemical management.

  4. Batch cleaning machines dump flux residues down the drain. This is not true, while it is possible to have the wash solution and rinse water go to drain the vast majority of batch flux cleaners sold in the US are “closed - loop” and zero discharge. Nothing goes down the drain. The wash solution stays in the machines wash tank and is reused until it is “loaded” with flux residue and the rinse water is recirculated through DI tanks which “clean” and remove and residual wash solution from each rinse. Nothing goes to drain.

How Do I Clean My PCBs?

PCBs are the backbone of electronic devices and must be kept clean to ensure accurate function. There are several ways to clean PCBs, but the most effective method is often determined by the specific type of PCB and its condition.

Some general methods for cleaning PCBs include using a vacuum cleaner with a dustbin, using a solvent-based cleaner, or soaking in hot water and detergent. For more delicate PCBs, users can try using a ultraviolet light or an ultrasonic cleaner.

The most common method is manual cleaning. This involves using a Phillips head screwdriver and an appropriate blower or vacuum cleaner. Equipment-assisted cleaning uses special tools to remove contaminants from the PCB.

Another approach is thermal oxidation. This method uses heat to oxidize contaminants on the PCB. Once the contaminants have been oxidized, they can be removed using a solvent or abrasive.

No matter how PCB cleaning is done, it's important to use caution and follow the manufacturer's instructions. Incorrectly performing PCB cleaning can lead to harmful chemicals being released into the environment, damage to the device, or even injury. always use proper safety equipment when cleaning a PCB.

Is Cleaning Vinegar Okay to Use on PCBs?

PCB cleaning can be done using a variety of methods, but all of them have the potential to damage the circuit board. Some of the most common methods used for PCB cleaning are heating the board with a soldering iron or an oven, scrubbing it with a chemical solution, and ultrasonic cleaning.

All of these methods have their own benefits and drawbacks. Heating the board with a soldering iron or an oven is effective in removing dirt, oils, and solder residues, but it can also damage the circuit boards if not done carefully. Scrubbing with a chemical solution can remove stubborn dirt and grime, but it can also damage the surface of the circuit boards if not applied correctly. Ultrasonic cleaning is considered to be gentle on circuits boards, but it cannot remove solder residues as effectively as other methods.

A lot of people are unsure about using cleaning vinegar as a means of cleaning PCBs. While it has been successful for DIY projects, it is not recommended for commercial use because the acid can etch the surface of the PCB. There are other, safer means of cleaning PCBs that should be used in this situation.

Is Acetone Okay to Use on PCBs?

No, even though Acetone is a common, low-cost solvent used in industrial and household cleaning products. Acetone should only be used on surfaces that are completely dry. If it is used in a wet environment, it can cause fires.

If you are looking for an effective, safe way to clean your PCBs, using a few common cleaning solutions is the best option. Always be sure to read the instructions that come with the product before using it, and be aware of the potential dangers associated with each method.

Is Isopropyl Alcohol Okay to Use on PCBs?

Yes! Isopropyl alcohol is a common solvent used in many household cleaning products. It is also safe to use on PCBs. However, like acetone, isopropyl alcohol can cause fires if it is used in a wet environment. DON'T spray a cleaning agent directly on the PCB surface.. Spray your cleaner onto a cloth first and then gently wipe the cloth over the surface.

If you are looking for an effective, safe way to clean your PCBs, using a few common cleaning solutions is the best option. Always be sure to read the instructions that come with the product before using it, and be aware of the potential dangers associated with each method.

Where Can I Buy a PCB Cleaner?

There are many places where you can buy PCB cleaners. Some stores carry specific brands, while others carry a variety of different chemicals. It is important to read the ingredients before buying a cleaner, as some may contain toxins that could damage your equipment.

What Toxins Can Damage my PCBs?

There are a few toxins that can damage PCBs. Acetone is the most common, but other chemicals can also be harmful. Some of these include formaldehyde, methanol, and ammonia. It is important to be careful when using cleaners, and to follow the instructions that come with the product. If you have any questions about using a cleaner, contact the manufacturer or your electronics retailer.

Why Should The PCB Be Scrubbed and Cleaned Before Soldering?

PCB cleaning is an essential step in ensuring the longevity of your electronic devices. Over time, flux residue can accumulate on boards and cause heat transfer problems, which can lead to overheating and failure.

Soldering flux removal is the most common way to clean PCBs. This process uses a hot iron to remove the flux residue from the board. However, this method is only effective if done correctly. If done incorrectly, soldering iron heat can damage components on the board and cause them to fail.

Chemical cleaning is another option for removing flux residues from PCBs. This approach uses chemicals to break down the flux residue and remove it from the board. However, chemical cleaning is more time-consuming than soldering flux removal and may not be effective if there are large amounts of flux residue on the board.?

What Are the Pros and Cons of PCB Cleaning?

The pros of PCB cleaning include the removal of harmful chemicals and pollutants from PCBs. The cons of PCB cleaning include the potential damage that may be caused to the PCBs. It is important to consult with a qualified professional prior to starting the cleaning process.


  • PCB cleaning can help to improve the overall performance of a computer system.

  • It can also help to remove contaminants that may be causing problems with the computer's operation.

  • PCB cleaning is often fast and easy, making it a good choice for those who need their computer system restored quickly.


  • PCB cleaning can occasionally result in the removal of critical components or even the entire motherboard.

  • Some types of PCB cleaning may require the use of special equipment or chemicals that may be harmful if swallowed.

PCB Cleaning: Conclusion

PCB cleaning is a necessary process for the electronics and device manufacturing industry. This guide provides you with step-by-step instructions for using a variety of PCB cleaning methods. Be sure to consult with a qualified professional before starting the cleaning process. There are many different types of PCBs and each requires a specific method of cleaning; consult your manufacturer or technical support staff for specific instructions on how to clean your particular type of PCB.

PCB cleaners come in various forms, including solvents, detergents, and surfactants. The most common type of cleaner is an emulsion solvent which includes water, oil, or glycol as the main ingredients. These cleaners work by dissolving oils and grease on the PCB surface while also breaking down organic matter.