Solar panels don’t essentially need cleaning. Over their 30+ year lifespan, you will get a film of dirt and if you can get them periodically cleaned, it will keep the performance at optimum – but not essential for operation.
Taking the situation to the extreme. The Mars solar-powered rovers are still working fine (except dodgy wheels). What makes photovoltaic so great are no moving parts in the system. The Martian dust-covered panels are working fine, well after their expected 90 day operational period.