Since we're throwing stuff at the wall how about flexible solar panels wrapped like a tank tread that roll past a stationary wiper arm?

What happens when the pad gets choked out with dust?

Great Mars-dust-wiper pads have little Mars-dust-wiper pads upon their backs to wipe 'em.

And little Mars-dust-wiper pads have lesser ... pads, and so ad infinitum.

It's pad's all the way down.

Squeegee then. You get the idea.

I'd go with a brush, actually.