WHO OR WHAT HAS BEEN CLEANING THE PANELS OF THE MARS ROVER?

It's happened 5 times now. Lol Wikipedia doesn't even have a smart answer "One theory is that wind currents in craters aid in cleaning events, and also if the rover is sloped, this is speculated to help remove dust.

The term started being used in 2004 as the Mars Exploration Rovers' (MER) solar panels started to benefit from these events."