As a follow-up to Does cosmic dust pose a problem for long-term satellites, telescopes and probes?, assuming satellite's long duration stay in Earth's orbit – let's for the sake of argument assume a run-of-the-mill communications satellite in Geostationary Orbit (GEO) – would its solar panels gather dust and require cleaning?
What is the rate at which this dust would gather, or if that is unknown, how fast do solar panels of GEO satellites deteriorate due to external causes that can't be attributed to material degradation due to exposure to solar radiation, solar wind, micrometeorites and other causes unrelated to persistent dust covering solar cells?
Additionally, assuming this can be identified as a genuine concern, what techniques can they employ to clean their solar panels or help mitigate persisting dust problem?