[Rio]

They need to drive it to a car wash.

[Phlyer]

They need to drive it to a car wash

A few years ago the solar panels looked like this and they were afraid they would have to shut the rover down. In the distance, just as they were powering down for the local night, the camera caught an image of a dust devil.

When they powered it up the next (Mars) morning, they had a lot more power. The dust devil had passed directly over the rover and cleaned off the panels.

So I guess the right thing is to hope for another dust devil - the Mars equivalent of a car wash. However, at a top speed of less than 1 mph, they won't have much luck trying to chase one down.