Blue MicroFiber Towels
I got a bunch of MicroFiber towels at Sam's Club. Best thing in the world for gentle cleaning. My tricks - I use a stepladder that does NOT lean on the side of the A/S and I've sewn three of the towels together end to end. Wet them down and simply toss them on the roof, skylight, etc. and gently drag them back towards me. To dry, I use clean towels that have been wetted, then wrung out thoroughly. I don't "scrub" the skylight, or even the clearcoat for that matter, because the dirt can be abrasive, but just let the weight of the wet towels do the job.
Be very careful with detergents - many contain ammonia which is murder on all polycarbonates and plastics - they will make your skylight haze over. Excepting for tar, most stuff will come off of the A/S without using any detergent whatsoever. (Dried bug stuff - leave a wet towel on soaking it for 5-10 minutes.). Tar? WD-40, which I do follow up with a mild detergent solution to get the WD off.
.......... Mine is overdue now, it's definitely time to do it at least once more before the weather turns very cold.
Today is a gift, that's why they call it the present.