Manual Cleaning: Techniques, Chemistry, and Instrument Disassembly

Why Manual Cleaning Is the Foundation of Sterile Processing

No sterilization method—steam, ethylene oxide, or low-temperature plasma—can penetrate and destroy pathogens that are shielded inside dried blood, tissue, or biofilm. Manual cleaning removes that organic burden before any disinfection or sterilization step begins. If cleaning fails, sterilization fails, and patients are at risk. For this reason, manual cleaning is considered the most critical step in the entire sterile processing cycle.

Reading the Instrument Manufacturer's IFU First

Before you touch an instrument with water or detergent, you must locate and read the manufacturer's Instructions for Use (IFU). The IFU is a legally required document that specifies exactly how that instrument must be cleaned, disassembled, brushed, rinsed, and dried. Key details to record from every IFU include:

• Maximum water temperature — Heat denatures proteins and can bake soil onto surfaces or damage instrument components. Many IFUs specify warm water (commonly around 110 °F or lower) for the wash step; always check the specific instrument's IFU.
• Required brush diameter and type — Using a brush that is too small leaves soil; one that is too large can damage a lumen or channel.
• Detergent type — Enzymatic, neutral pH, or instrument-specific chemistry. Never substitute without checking the IFU.
• Disassembly requirements — Multi-part instruments must be fully disassembled before any water contact so that water and detergent can reach every surface.

IFU binders and laminated IFU cards should be kept at the decontamination sink and consulted every shift, not memorized and assumed.

Personal Protective Equipment in the Decontamination Area

All work in decontamination is performed in a full PPE ensemble: fluid-resistant gown, surgical mask or face shield, heavy-duty puncture-resistant gloves (not exam gloves), and shoe covers. Eye protection is mandatory—aerosolized contaminated water is an exposure risk. PPE is donned before entering the decontamination area and removed before leaving. Never carry PPE into clean areas.

Disassembly: Getting to Every Surface

Instruments that are not fully disassembled before cleaning cannot be cleaned effectively. Rules for disassembly:

• Box-lock instruments (hemostats, clamps, needle holders): open the ratchet to the first ratchet position and open the box-lock fully so the pivot area is accessible.
• Multi-part instruments (retractors with removable blades, laparoscopic instruments with detachable tips): separate every component per IFU.
• Lumen instruments (trocars, cannulas, suction tips): remove any obturators, valves, or stopcocks; flush through the lumen.
• Flexible endoscopes and their components: follow the specific channel-access steps in the IFU; use the channel brush specified by the manufacturer.

Place all components together as a set so nothing is lost during cleaning.

Cleaning Chemistry: Enzymatic vs. Neutral pH Detergent

Enzymatic detergents contain enzymes (typically protease, lipase, and amylase) that actively break down proteins, fats, and carbohydrates in organic soil. They work best at the temperature specified by their IFU and lose activity if the solution is too hot, too dilute, or too concentrated. Enzymatic solutions are single-use: discard after each sink load or per manufacturer guidance.

Neutral pH detergents (pH approximately 6–8) are general-purpose cleaners that do not contain active enzymes. They are appropriate for routine cleaning of instruments that do not carry heavy organic soil, and for facilities where the IFU permits their use.

Neither type should be mixed together unless the product manufacturer specifically permits it. Always dilute to the manufacturer-specified concentration—more is not better. Over-concentrated detergent leaves residue that can interfere with sterilization.

The Wash-Rinse-Rinse Sequence

Manual cleaning follows a structured sequence:

1. Pre-rinse at point of use (done in the OR or procedure area before transport): removes gross soil and prevents drying.

2. Wash step: submerge instruments in detergent solution, brush all surfaces systematically—serrations, box-locks, hinges, lumens, and exterior surfaces. Keep instruments below the waterline while brushing to prevent aerosolization of contaminated droplets.

3. First rinse: remove all detergent and loosened soil with tap water.

4. Final rinse: use purified water (deionized or distilled) if the IFU requires it to prevent mineral spotting.

Maintain water levels to the fill lines marked on the sink. Overfilling increases splash risk; underfilling reduces the effectiveness of the soak.

Brushing Technique

Select the brush size that fits the lumen or feature being cleaned—it should contact the inner wall with slight resistance. Use a back-and-forth motion through lumens so that both ends of the brush exit the channel, ensuring the entire length is scrubbed. For serrations and jaw surfaces, angle the brush into the teeth. For box-locks, work the brush into the joint with the instrument held open. Inspect brush bristles before use; a bent or worn brush does not clean effectively and must be discarded.

Post-Cleaning Inspection

After the final rinse, lay instruments on a clean towel. Under a magnifying glass and inspection light, check:

• All surfaces for visible soil, blood, or tissue
• Lumens (hold up to the light—a lumen should show a clear light path)
• Hinge areas and serrations
• Any crevice, port, or joint

If any soil is visible, the instrument must be recleaned. Document each cleaning attempt in the lab log, including detergent lot number, dilution used, water temperature, and inspector initials. This documentation habit mirrors the quality records required in every accredited sterile processing department.

Scope of Practice and Safety Reminders

• Always check the IFU—never clean from memory alone.
• Keep all brushing submerged to reduce aerosol exposure.
• Report any sharps injury immediately per facility protocol.
• Discard single-use cleaning solutions after each use—reusing enzymatic solution is not safe practice.
• Never carry contaminated instruments uncovered through clean areas.