2.3 Manual Cleaning Methods

Manual cleaning is the cornerstone of decontamination. The guiding rule of the entire CS profession is that an item that is not clean cannot be disinfected or sterilized — soil shields microorganisms from heat, chemicals, and steam. Even where automated washers exist, many items require manual cleaning because of their design, material, or IFU, and heavily soiled items are pre-cleaned manually before automated processing.

When Manual Cleaning Is Required

• Instruments with dried or hardened soil (may need pre-soaking).
• Delicate items that automated washers could damage (microsurgical, ophthalmic, fiber-optic).
• Complex designs — lumens, hinges, ratchets, box locks, moving parts.
• When automated equipment is unavailable or out of service.
• When the manufacturer IFU specifies manual cleaning.
• Items requiring pre-cleaning before the washer-disinfector.

The Manual Cleaning Sequence

Step 1 — Sort and disassemble

Open all hinged instruments; disassemble multi-part devices per IFU; separate sharps and delicate items; group similar instruments for efficiency.

Step 2 — Pre-rinse (cool water)

Rinse under cold to lukewarm water (below 110°F / 43°C) to flush gross soil. Hot water makes blood proteins denature and coagulate — like cooking an egg — bonding them permanently to the surface. Flush lumens with a syringe or irrigation adapter.

Step 3 — Soak (if needed)

Soak in enzymatic detergent per IFU (often 1-10 minutes). Do not over-soak — prolonged exposure can harm finishes and promote corrosion. Change the solution frequently; once heavily soiled it loses effectiveness.

Step 4 — Wash / scrub (submerged)

Keep instruments below the water surface while scrubbing to prevent aerosolization — contaminated droplets that the technician could inhale. Use the right brush: lumen brushes sized to the channel, detail brushes for box locks and ratchets, soft-bristle brushes for delicate surfaces. Scrub interior and exterior, working from least to most soiled.

Step 5 — Rinse

Rinse thoroughly with treated/critical water to remove all detergent. Residue can interfere with sterilization, cause patient tissue reactions, and leave deposits that attract new soil. Flush every lumen completely.

Step 6 — Inspect

Visually check each item (use magnification when available) for remaining soil, and verify function: scissors cut paper cleanly, hemostats and ratchets hold, jaws align. If soil remains, repeat the entire cleaning process.

Water Temperature Guide

Key rule: Never use hot water for the initial rinse. Heat fixes blood protein onto the metal, making it nearly impossible to remove later.

Cleaning Chemistry

Water chemistry matters: pH and water hardness affect detergent performance and instrument life. Detergents are chosen to match the soil and the instrument:

Enzymatic detergent facts

• Protease digests proteins (blood), lipase digests fats, amylase digests starches.
• Optimal activity is at lukewarm temperatures — water too hot denatures the enzymes and destroys cleaning power; too cold slows them.
• Prepare fresh per IFU; enzymatics clean but do not disinfect.
• Always rinse thoroughly afterward.

Brush Selection and Care

Inspect brushes daily for bent or missing bristles; decontaminate after each use (run through the washer-disinfector); replace per policy; prefer single-use lumen brushes when possible.

Worked Scenario and Traps

Scenario: A technician fills the sink with hot tap water, drops in a tray of bloody hemostats closed, and scrubs them above the waterline. Three errors: hot water coagulated the blood, the closed box locks trapped soil, and scrubbing above the surface aerosolized contaminants. Correct practice is cool pre-rinse, open hinges, and fully submerged scrubbing.

Common traps: assuming the washer makes manual cleaning unnecessary for complex devices; reusing exhausted enzymatic solution; using a lumen brush that is too small; skipping inspection after cleaning. Cleaning verification — confirming soil was actually removed — is part of the job, not an optional extra.

Water quality is an underappreciated variable in manual cleaning. Hard water rich in calcium and magnesium leaves mineral spots and scale and can reduce detergent performance, while water with high chloride content contributes to pitting and corrosion. ANSI/AAMI ST108 defines water categories for each processing step, with the final rinse requiring high-purity (critical) water to avoid leaving residue and to protect the instruments. A technician who understands that the chemistry of the water itself, not just the detergent, affects the outcome will troubleshoot staining and spotting far more effectively.

Finally, never use abrasive pads, steel wool, or scouring powders on stainless steel instruments — they scratch the protective passivation layer, exposing the metal beneath and inviting rust and pitting that shorten the instrument's working life.