how do you clean it? Sand and crap is going to blow across that and I don't see a practical way to get it off. I'm not sure those panels are rated for people

how do you clean it? Sand and crap is going to blow across that and I don't see a practical way to get it off. I'm not sure those panels are rated for people walking across them, so robots? I can imagine that moss/algae is going to be a problem, as it start growing in the corners where all the dust gets trapped and is kept moist.