PowerWash Simulator has a few different cleaning modes to choose from. One of those categories is called “Specials,” and the jobs see you cleaning everything from a gnome fountain to a locomotive. A genuinely out-of-this-world level even takes you to the Red Planet to clean the Mars Rover and the mystery hatch.
If you open the level details menu once you arrive on the fourth rock from the Sun and scroll to the bottom, you’ll see the mystery hatch listed as the last item to power wash, netting you $0.50 for getting it clean. However, it’s not actually part of the rover itself, so don’t waste your time pouring over the ROV looking for it. Don’t worry, though: it’s nearby.
Climb on top of the rover, and look in the direction of its front-facing camera. To the left of that, you’ll see a small pyramidal structure just over a few small hills in the distance. If you follow the alien footprints on the ground leading away from the rover, they’ll lead you right to the mysterious hatch with a curious garden gnome standing watch nearby.
Simply clean that with the yellow nozzle to speed things up, and you’ll complete the job, considering you’ve cleaned the rest of the rover.
There’s no telling where the mysterious hatch leads — most likely to a secret Martian metropolis deep underground. Alas, PowerWash Simulator doesn’t let you explore what else might need cleaning in such a place (but there’s always DLC!). For more tips, head over to our PWS guides page to learn how to change clothes and how to use room codes.