Instrument Processing



In the United States, you are not required to sterilize your tools, but consider various recommendations to do so, including the CDC.

Four factors influence your decision for which process to use:

  1. Environmental/animal friendliness 

  2. Affordability

  3. Risk of cutting live tissue 

  4. Personal standards 

Infection Control: Creating Your Policies and Procedures

CDC: Guide to Infection Prevention for Outpatient Podiatry Settings    

CDC: Indications for Sterilization, High-Level Disinfection, and Low-Level Disinfection

APMA: Disinfection and Sterilization Guideline Recommendations for Podiatric Physicians 

Research recommendations in your area. For example: Boston Public Health Commission states that nail salons "must install and use either an autoclave or a US FDA registered dry heat sterilizer to sterilize multi-use tools". Although the Boston Public Health Commission writes about "nail salons", the focus should be about sterilizing multi-use tools.

According to the CDC:

  Sterilization should be used on critical items (e.g. tools that penetrate tissue that has a blood supply).

  High-level disinfectants can be used on semi-critical items (e.g. tools that come into contact with non-intact skin).

  Low-level disinfectants can be used on non-critical patient-care surfaces (e.g. foot stools) and equipment (e.g. tuning fork). 

Following CDC recommendations, the American Podiatric Medical Association (APMA) guidelines (last updated March 2019) recommend:

  High-level disinfectants (at a minimum) should be used on tools for manual debridement (e.g. nippers and curettes).

  High-level disinfectants (at a minimum) should be used on tools for mechanical debridement (e.g. burrs).

  With mechanical debridement you must use dust extraction equipment.


The APMA further recommends that heat stable instruments that have the "potential to break intact skin during ordinary use" (e.g. nippers, burrs, and curettes) should not rely on liquid chemicals for sterilization. Regardless of the terminal reprocessing method, APMA states that all tools must be thoroughly cleaned, as inorganic and organic materials that remain on the surface of instruments will decrease the effectiveness of disinfection/sterilization.

Canada has more clearly stated and stricter standards than the US for processing foot care instruments. See the Reprocessing Decision Chart from Ontario Agency for Health Protection and Promotion for all options for cleaning, disinfecting, and sterilizing (full document here). In Canada, foot care equipment is considered critical and requires sterilization.

What does this mean for practice? APMA refers to cleaning methods for manual (e.g. friction (rubbing/scrubbing with a brush) and fluidics (fluids under pressure)), as well as mechanical (e.g. ultrasonic cleaners or washer-disinfectors). The minimum required cleaning method would be using water and detergent with a brush and rinsing well and drying thoroughly before disinfection/sterilization. This may mean that you need multiple sets of tools so clients aren't exposed to improperly disinfected or sterilized tools. 

Not convinced? Read about these unfortunate cases in the US (back-up link).

Multiple Sets of Tools

"An adequate supply of clean and disinfected or sterilized patient-care instruments should be brought to (or be available at) the off-site facility so that items do not have to be reprocessed at the off-site location to maintain clinical workflow."

See "Reprocessing of Medical Devices with Off-Site Podiatry Care", page 31, of the full guide for more details.

Nippers and reusable burrs need to be cleaned prior to disinfection/sterilization. This means you need multiple sets of tools. Good nippers can cost over $100, but what is a good nipper? The features of a nipper includes the type of stainless steel, the handles, the cutting edges, and springs and hinges. Some of the least expensive nippers (and poorest quality) are available on (this one is actually $8.50). These can be considered "student grade" nippers after proper refining. It will help you afford the same number of nippers as you see clients in one day and allow for proper reprocessing of your nippers.


Type of Stainless Steel. Inexpensive nippers are typically made from 201 stainless steel, which is the least expensive type and not used for surgical tools (but nippers are not surgical tools and it is allowed in the US). 201 stainless steel is said to rust if exposed to the elements (water and salt), so care must be taken to protect it by reducing its contact time with water and salt (clean on the same day of use and dry after getting wet). 


Handles. The handles may be loose. You can tighten the screw(s), add lock tight if it doesn't stay tightened, or treat it like a rivet. Clipper Shack explains with a video for how to fix the handles.

Cutting edges. Inexpensive nippers have gone through the first process of manufacturing. They have not been refined through proper sharpening. Find a blade sharpening business in your area to see if they sharpen nippers. Excellent quality nippers are made with surgical grade, softer stainless steel. They dull sooner and need occasional sharpening. Nipper sharpening services are likely in an area where there are podiatrists. If you would like to sharpen your own nippers and offer services in your area, consider a Nipper Sharpening System. Uneven edges can be corrected with sharpening as seen in a Clipper Shack video. Or, you can hand sharpen nippers as shown in this video.

Springs and Hinges. These are moving parts that need to be lubricated regularly.

Multiple Sets of Burrs. Start out with disposable sanding caps/bands until you can afford high quality burrs with your high quality drill (NEVER USE A DREMEL). Using high speed rotary burrs causes vibration and friction (heat), which can cause discomfort and pain for clients. Vibration can be reduced with use of balanced, reusable burrs and low vibration drills. Sanding caps/bands may have varying thicknesses, which can add to vibration. Friction can be reduced by keeping burrs at the recommended speed (usually 10,000 rotations per minute) and touching down lightly and moving to new areas frequently.

Your hands will also benefit from low vibration debulking (protect your nerves) and well-lubricated nippers on debulked nails (protect your joints).

High-Level Disinfection versus Sterilization

High-level disinfection and sterilization both eliminate all microorganisms. The difference is that sterilization also eliminates bacterial spores, which aren't eliminated by high-level disinfection. Read more about the differences from the CDC.

What harmful bacteria make spores?

Bacillus anthracis - Anthrax

Clostridium botulinum - Wound botulism

Clostridium tetani - Tetanus

Clostridium perfringens - Gas gangrene

Clostridium difficile - C. diff

Dry Heat Sterilization

Dry heat sterilizers rely on time, temperature, airflow rate and air distribution, and load configuration. They typically use convection to dehydrate and destroy microorganisms. There are two forms of convection: static air and forced air. Static air convection is preferable for lightweight items that could blow around. Because there is no fan, the chamber temperature is less uniform. Forced air convection uses a fan to keep temperature consistent in the chamber, which is ideal for destroying all microorganisms and spores.


Because dehydration is the mode of action, water content affects efficacy. The more microorganisms and spores there are on the surface of the tools, the longer it takes to destroy them all. This is why you must thoroughly clean your tools before beginning a cycle, ideally with manual cleaning and ultrasonic cleaning. It is also why dry heat sterilization takes 60 to 150 minutes depending on the set temperature, rather than 30 minutes in a gravity displacement sterilizer (autoclave). Tools exposed to dry heat must also cool down. There are dry heat sterilizers with cool down modes that have vents and HEPA filters to speed up the cool down process. The simplest method is to keep the chamber door closed and let it cool down on it's own, which does take hours. That's why it's helpful to have a chamber large enough to hold all of your tools and let it cool down overnight. Unless you prepackage your tools, you don't want them to sit around on a counter, cooling down, and collecting microorganisms. For an in-depth breakdown of dry heat sterilizers, check out this member only page.


Dry heat sterilization requires mechanical, chemical, and biological indicators and a sustained temperature over a period of time (e.g. I process my tools at 170 degrees Celsius for 2 hours, which is more time than the minimum time required). See below if you are interested in setting up for dry heat sterilization with an FDA registered dry heat sterilizer.

Autoclave Sterilization

Read about Autoclaves from the CDC website.

Liquid Chemical Disinfection

According to the CDC, liquid chemicals "should be restricted to reprocessing critical devices that are heat-sensitive and incompatible with other sterilization methods". With that said, nurses and podiatrist continue to use it. Instructors continue to recommend it. I don't recommend using liquid chemicals for foot care tools and neither does the CDC.


Please be environmentally responsible. If you use liquid chemical disinfection, follow the Safety Data Sheet (SDS) for appropriate use (section 1), first aid measures (section 4), and disposal (section 13). MetriCide 28 is a high-level disinfectant and requires following Federal, State, and local regulations for disposal. EnviroCide is an intermediate-level surface disinfectant and is used as a "hard surface cleaner and disinfectant". CaviCide is also an intermediate-level surface disinfectant and the manufacturer's instructions state it is not to be used as a "terminal sterilant/high level disinfectant". EnviroCide and CaviCide also require verification with Federal, State, and local authorities for disposal. Consider your choices for sterilization/high-level disinfection, the environment, and efficacy.

Please note that SDS information changes and you must have the most recent SDS. Simply searching the internet for "CaviCide SDS" will bring up an outdated SDS from 7/14/2015 stating that CaviCide can be poured down the drain - wait! You must go to the manufacturer's full website for the updated SDS (CaviCide has one dated 12/4/19). Very often liquid chemical disinfectant disposal instructions (found in section 13) will direct you to follow Federal, State, and local regulations. I was informed that any liquid chemical disposal had to be removed by a professional disposal company and I would need a hazardous waste generator ID. Long story short, for me, it's too expensive to discard properly. This does not mean pour it down the drain! Keep searching for an environmentally friendly way to sterilize/disinfect your tools and get verification from Federal, State, and local authorities for how to discard liquid chemicals. Refer to the SDS for disposal of the container, as some indicate that they cannot be recycled.


Some chemicals (like MetriCide 28) additionally need an activator and solution testing strips. Only use chemicals as directed by the manufacturer and document on a Solution Testing Log Sheet.

The problem with sterilizing with high level disinfection/sterilization agents is that there are no indicators that you can use to ensure the spores were killed. Even at the disinfecting level, you must test your chemicals regularly to ensure they are still potent. Any unused chemicals after the expiration date need to be disposed of in accordance of your local, State, and Federal guidelines. High level disinfection is meant for heat sensitive instruments (things that can melt) and can be damaging to your expensive instruments. There are plenty of foot care nurses and podiatrists who use high level disinfectants, but 1) are they using the chemicals responsibly? and 2) are they disposing of the chemicals responsibly?


Responsible use of high level disinfection/sterilization agents includes:


-Cleaning instruments thoroughly before disinfection, best done with an ultrasonic cleaner.


-Leaving the instruments submerged for the necessary amount of time.


-Rinsing the instruments off with water and drying before contact with the client.

-Testing the solution regularly and keeping a log.

-Disposing of the solution after the expiration date (set when the bottle is opened).

-Disposing of the solution per local, State, and Federal guidelines (probably not down the drain).

Know Your Chemicals

In addition to understanding the SDS, knowing the chemical you're working with is also important.

These chemicals have been tested on animals.

FDA-Cleared Sterilants and High Level Disinfectants with General Claims for Processing Reusable Medical and Dental Devices. This content is current as of 09/25/2019; however, manufacturers may have made changes.

Search for chemicals on the EPA website.


Common Sterilants and High Level Disinfectants include:


Mode of Action: Acts on microorganisms by causing alkylation of cellular components that alters the protein synthesis of DNA and RNA

US EPA - Pesticides - Reregistration Eligibility Decision (RED) for Glutaraldehyde Reregistration Eligibility Decision (RED) for Glutaraldehyde

CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (2008) Glutaraldehyde

Peracetic Acid

Mode of Action: Denatures the proteins and alters the permeability of the cell wall

Peracetic Acid Results - AEGL Program
Peracetic Final AEGL Document

Peracetic acid AEGL Technical Support Document (PDF)

CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (2008) Peracetic Acid



Mode of Action: Kills microorganisms by alkylation of cellular components and acts directly on nucleic acids

Evaluation of Ortho-phthalaldehyde in Eight Healthcare Facilities

CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (2008) OPA

Isopropanol/Isopropyl Alcohol

Mode of Action:  Dissolves the cell membrane (phospholipid bilayer)

U.S. EPA. Provisional Peer-Reviewed Toxicity Values for Isopropanol (Isobutyl Alcohol). U.S. Environmental Protection Agency, Washington, DC, EPA/690/R-14/009F, 2014.

Hydrogen Peroxide is an oxidant to metal.

Bleach is corrosive to metal.

Dry Heat Sterilization Set Up