I'm not sure much cleaning is really needed. Last summer, I was out there with a bush
and hose, whenever I saw bird droppings.
But, this winter?? Nope.. I didn't want to mess with draining the hose etc..
It was too cold for me anyways.
Pretty soon, I noticed those bird droppings disappeared after a while.
The sun, snow and rain keeps them pretty clean.
I've seen Ed Begley, Jr sweeping the dust off his panels..
And it seemed to be more of a (TV) way to get out of the house and away from his wife..
Sort of his Man-Cave on the roof..
When his wife invaded his space up there, he hid the ladder!!
I would be leery of installing panels where there are wires or limbs above them.
(I have a few limbs right above some of my panels).
And, if you can mount some kind of wind spinner on top of the upper edge,
you might be able to keep birds from perching on the them/making a mess.
I wonder if a run of small nylon line across the perch area would work?
Leave it loose, so it will be too floppy to perch on!
And be in the way of perching on panel frame..
I've seen some kind of spike-wire on outdoor strip-mall sidewall overhead shelter.
And in the over-head in parking garages.
They use it to keep the birds from nesting above cars..