Pre-Cleaning End-Face Inspection and Contaminant Classification‌
Before any physical cleaning action is taken, the optical fiber end-face of the transceiver is examined under high magnification to identify the exact type, location, and severity of contamination present. Common contaminants include loose dust particles, faint oil films from human skin contact, residual adhesive traces, and tiny dried condensate spots that accumulate after long-term operation in humid environments. Technicians map the distribution of every visible mark across the core, cladding, and surrounding ferrule surface, and distinguish between removable surface contamination and permanent scratches or pits that cannot be resolved through cleaning. This step prevents blind, unnecessary wiping that could grind hard trapped debris into the glass surface and create permanent, irreparable damage to the polished end-face.

This careful classification ensures that every subsequent cleaning step is targeted exactly to the contaminant type, rather than applying a generic wiping process that often creates more problems than it solves.

‌Dry Cleaning for Loose Particulate Removal‌
For end-faces with only light, loose dust and no sticky or oily residue, a precision dry cleaning process is used to lift particles away without introducing any liquid that could leave new streaks behind. The cleaning medium makes contact with the end-face under controlled, even pressure, moving in a single consistent linear path across the surface rather than being twisted or rubbed in circular motions that can spread contamination across a wider area. Every section of the cleaning surface is used only once before being replaced, so removed particles are not re-deposited back onto the same end-face during subsequent passes. After the dry cleaning step is complete, the end-face is re-inspected immediately to confirm all loose particulate matter has been fully lifted away.

This gentle process is the lowest-risk first step for most routine contamination cases, and it resolves the majority of common field issues without exposing the polished glass surface to any additional chemical agents.

‌Wet-to-Dry Process for Persistent Film Residues‌
If dry cleaning leaves behind thin, persistent oil films, faint condensate rings, or sticky residue that cannot be lifted with dry contact, a controlled wet-to-dry cleaning sequence is applied. A tiny, precisely metered amount of fast-evaporating, residue-free solvent is applied to a fresh section of the cleaning medium, which is then drawn across the end-face in one smooth, continuous motion. The solvent dissolves the sticky film on contact, and the immediate follow-up dry portion of the same wiping path lifts the dissolved residue away completely before the solvent can evaporate and leave a new faint ring behind. After this process, the end-face is inspected once more under magnification, and a quick dry pass is applied if any faint residual trace remains before the transceiver is reconnected to the network link.

This two-stage wet-to-dry method is aligned with established industry inspection standards, and it reliably restores the end-face to a fully clean condition that supports stable optical power transmission and consistent long-term link performance.