Fiber optic adapters (mating sleeves) are used to mechanically connect two fiber connectors. A fiber adapter consists of two main parts: the connector alignment sleeve and the adapter housing.Connector alignment sleeve is usually a split “C” and is made from a hard, low-wear material such as Zirconia (a type of ceramic ) and phosphor bronze.
The alignment sleeve is the most critical part since it provides the alignment of two connector ferrules.
In the late 1990s, The Technologies studied the reliability of fiber optic enclosures in outside plant environment (field enclosures). They assembled a report on the benefits of fiber connection cleaning in those fiber optic OSP enclosures. The statistics showed a significant improvement after connector and adapter cleaning.
The best practice is to clean an adapter or connector thoroughly before mating whenever your insertion loss suddenly increases.
The most convenient way to clean it is with the fiber optic cleaning swabs.