Og tele cleaning

Hi All,
I got an og tele when it came out to read license plates of cars entering our development during daylight. Few months later plates are not readable. I suspect lens has become dirty. But og tele has only a small hole for lens. Any idea how to clean it?


I don’t have any OG or OG Telephoto cams but the Lens doesn’t look that small to me, got a picture of the actual cam? I have V3, WCO, V3 Pro cams and I clean them with eyeglass wipes and a microfiber cloth.