Enterprise space adventurers:

Sometimes it is better to be lucky, fate,
than very good.

John C Redfern Author, Economist, Consultant

In space there is no such thing as a "perfect set of winds to "carwash" the Rover Opportunity. I think someone not something did it. I do not believe what was seen on the surface is the "heatshield". A heat shield does not have a robotic arm, antenae ports, or wheels. No matter, NASA is never going to come clean, ever. They will lie time and again. That's why you get censored images with blurrs and smudges. Yet when they want to, they can produce perfect pictures.

A unknown process that 'swept away dust layers' on the rover? Hum...why didn't the article or the scientific community present a hypothesis for the 'swept away dust layers'?
Even the common sense approach of thought, might lead one to the idea of 'deposition and accumulation of frost during the martian night elevated the accumulated dust particles from the solar panels on the rover. During the dawn hours, the solar panels were aligned, in such a way, that the incoming solar light lead to a scrubbing or melting of the carbon dioxide and water vapor frost. Thus, the end result was a natural cleaning, much like rain washes away dirt and dust from the leaves of trees or how frost cleans a car window. On Earth, the residual grim on solar cells, is a by-product of bacterial life. Hence, windex is often needed to clean ones car windows. As with Mars, the mechanism isn't fully understood, but chemical compositions of 'Martian Frost' may include ammonia and other peroxides that facilitate the increase solar absorption and power output.

Well, then too maybe "Rosie" from "The Jettsons" happened to be flying around and decided to clean her robotic world!

Or was it those damn-furry little 'Marsets' that live in the caves? The ones that have bio-ethical rights to existance and will greet the human explorers and colonist and prevent them from 'oh God forbid...terraforming Mars!"