FAQ: Fiber Optic Cleaning Solutions

Below are the FAQs submitted by customers regarding AFL fiber optic cleaning solutions.

Q: Why Clean Fiber Optic Connectors?
A: Fiber optic communication is achieved by transmitting a beam of light down an optical fiber. Typical fiber optic cores (signal carrying portion) are 9µm single mode and 62.5µm multimode. To put this in perspective, a typical human hair measures 90µm in diameter.

This makes cleanliness of optical connections (SC, LC, MTP, etc.) extremely important. Common contaminates such as dust, dirt, oils, etc. may be larger than 9µm and can attenuate or completely block an optical signal much like dirt attenuates visible light transmitted through windows.

Many optical networks have tight loss budgets. Dirty connectors can quickly exceed the allowed loss. Dirty connectors are a common cause of costly down time for networks. Cleaning connectors is quick and inexpensive - network downtime and service calls are costly. It is a good practice to clean and inspect connectors each time they are disconnected. Dust and dirt are everywhere.

Q: What are “common contaminates” – What am I cleaning off?
A: A few of the common connector contaminates are listed below:


  • Dust and dirt are a fact of life. There are always particles airborne and on surfaces. Slight air currents can transport them to exposed fiber optic connectors.

Metallic particles

  • Connector bodies and fiber housings are commonly made from plated metal (especially military connectors). Normal wear and tear will scrape off the platting in tiny particles. Normal wear and tear of hand tools can also produce tiny metal particles. Metal particles are similar to dirt with two exceptions:
    • A charged connector (easily produced by dry wiping) is a magnet for metallic particles. They will literally jump to an electro-statically charged connector.
    • Metallic particles are by nature abrasive. Dry wiping can cause the fiber end to be scratched and damaged by metallic particles.


  • Human skin is naturally oily. Contact with an optical connector virtually guarantees instant contamination of the connector end face.
  • In the field, other oils such as WD-40, hydraulic fluid, etc. may be in use. These will contaminate the connector and can be just as stubborn to remove as WD-40 streaks from a window. Always remember, the “signal” is a beam of light. Cleanliness really means – optical clarity.

Q: Do I need to inspect connectors – or is it sufficient to just clean them all?
A: Yes, you should always inspect fiber connectors prior to reconnecting them. Multiple cleans may be required to remove some contaminates. Further, inspection is needed to identify damaged fiber ends (cracked glass, pits, etc.).

Q: Can I use IPA Alcohol to clean fiber optic connectors?
A: IPA is commonly used to clean fiber optic connectors. However, it is not an ideal cleaner for connectors. If you do use IPA, make sure it is optical grade 99%. Never use common drug store IPA (rubbing alcohol) – approximately 70% pure.

Concerns with using IPA Alcohol for optical cleaning:

  • First, even 99% IPA can leave a residue behind.
  • IPA is hydrophilic. It has a great attraction for water. When IPA is exposed to air, it takes on atmospheric moisture, which reduces the purity.
  • Does the water content of your IPA matter? Yes.
    • When water dries, the evaporation process draws in air. With the air come dust particles and other impurities to recontaminate the connector.
    • Slow drying is undesirable for cleaning connectors in adapters because a small amount of remaining IPA caught between connectors actively transmitting high signal power can flash evaporate the IPA and damage the fiber end face. When this happens, the connectors must be replaced.
  • Safety: IPA is flammable and must be handled with appropriate Hazmat precautions and paperwork.
  • IPA cannot be shipped by air. Thus, when technicians fly to a jobsite, they cannot bring their IPA with them. Instead, they may end up running to a drug store to pick up a bottle of rubbing alcohol. While convenient, it definitely is not optical grade!

Q: If IPA alcohol is undesirable for fiber optics, what cleaner can I use?
A: AFL offers optical quality cleaning fluids specifically designed to meet or exceed the cleaning ability of IPA without the hazards and limitations. AFL cleaning fluids are nonflammable, not hazardous, and not regulated (including air-cargo). In a word, they are safe.

FCC2: Fiber Connector Cleaning Fluid. This is a very fast drying cleaner specifically designed to work with CCT cleaning sticks to produce an effective and safe connector cleaning solution.

FPF1: Fiber Prep Fluid. This is similar to FCC2, but it is formulated to dry slower. This makes it easier to use with fiber wipes to clean stripped fiber prior to fusion splicing or adding connectors to fiber ends.

Q: Can I take FCC2 Fluid or Fiber Prep Fluid on my air flight?
A: While this is ultimately up to the individual TSA agent at check in, FCC2 fluid and Fiber Prep Fluid meet the guidelines for carry on fluids. If asked, refer the TSA agent to the product ratings listed each can:

  • Health = 1
  • Flammability = 0
  • Reactivity = 1

Each pump bottle contains 3oz (85 grams) of cleaning fluid.

Q: What is the difference between Type A & Type B Cletops?
A: Both versions have a retractable metal cover over the cleaning tape measuring approximately 1.5” x 0.75” (38mm x 19mm). The difference:

  • Cletop Type A units have two slots specifically designed to accept 2.5mm ferrules.
  • Cletop Type B units feature an open rectangular access to the cleaning tape that accepts all the connectors the Type A will accept and more.

Cletop Type

Type A

Connectors Supported

SC, SC2, FC, ST, DIN, D4

Cletop Type

Type B

Connectors Supported

SC, SC2, FC, ST, DIN, D4

MU, LC, MT, (MPO & MT-RJ without pins), E-2000, BICONIC

Q: What is the difference between the Cletop and Cletop-S models?
A: The difference:

  • Cletop was the original model.
  • Cletop-S is the second generation cleaner featuring improved ESD protection in a more ergonomic package. The Cletop-S improves tape maintenance by packaging the tape in a drop in cassette.

Cletop Type
Tape maintenance (Cletop vs. Cletop-S)
Screwdriver required to open case. Tape must be loaded and manually threaded around take up spool

Cletop Type
Cletop -S
Tape maintenance 
(Cletop vs. Cletop-S)Tool-free case design Drop-in replacement tape cartridge


Q: What model does AFL recommend?
A: Cletop-S Type B (Cletop-SB).

Q: What is the difference between the blue and white tapes?
A: The difference:

  • Blue Tape was designed for the Cletop Type A for cleaning 2.5 mm ferrules. When the newer connectors with reduced sized ferrules came on the market, the tip would catch on the tape fabric. Solution: White tape.
  • White Tape is a finer weave that was designed to minimize the tendency for smaller connectors to snag in the tape weave.
  • There is no significant difference in cleaning performance between the blue and white tapes.
  • The choice is up to you. But, AFL recommends using white replacement tapes in all your Cletop and Cletop-S cleaners.

Q: Can I use a Cletop Cassette Cleaner to clean an E-2000 connector?
A: Yes. It can be done, but it is not easy. This is not a fault of the Cletop, but due to the self-closing door covering the E2000 ferrule. Cleaning the E2000 with any other means presents the same issues.

Recommended Cletop: Use a Type B with the open window. AFL recommends the Cletop -S type B, but the regular type B would work equally well. The Type A Cletops have two openings to guide 2.5mm ferrules - this would not be helpful with the E2000 connector.

Procedure: Open the E2000 end-face door and slide it down the side of the connector as far as it will go. Hold the connector in one hand using a finger or thumb to hold the door open. Using the other hand, hold the Cletop and open the cleaning window. Wipe the ferrule end-face across the cleaning tape being careful not to let go of the door.