As for mild oxidation, the metal surface of the switch loses its original luster and turns to a light yellow or light brown color. This situation is mostly caused by the switch’s being placed in a humid environment for a short period of time or its natural aging.
The switch with mild oxidation can still be used, but its sensitivity will significantly decrease. Further oxidation may occur, so it is recommended to handle it promptly:
- you can first wipe the contacts with absolute ethanol or gently rub the oxidized surface with 600-800 mesh fine sandpaper in one direction.
- After cleaning, apply a layer of anti-oxidation silicone grease on them.
As for severe oxidation, the metal components of the switch lose all their luster, and a thick layer of black or dark brown film adheres to the surface (copper materials will form green rust); this situation is mostly caused by the switch’s being exposed to large temperature differences, high humidity, chemical corrosion environments, or severe overload and sparking.
Severe oxidation of the switch poses serious safety hazards. The oxide layer and rust layer are high-resistance layers, which will cause severe heating and increased voltage drop; when the oxide layer causes poor contact and current passes through, the terminal gap will generate electric sparks and arcs, accelerating erosion; the oxidized part is covered with rust, dust, and moisture, resulting in increased leakage between terminals on the surface, and in a humid environment, it is prone to short circuits and tripping due to leakage.
In conclusion, severe oxidation of the switch is not recommended for continued use; replacing it directly is the best option.