"Littered?" Seriously? The amount of artificial objects on the Moon and Mars combined would fit in one Walmart store.
From Apollo 11 - 17, what was the total hours on the Moon? A day and a half, maybe? In that brief time, we managed to dump, like ... what? 11 metric tonnes of trash on the planet? Not too shabby for a couple day's work! Imagine if we'd stayed a whole year! Good thing the Moon has those plentiful, fathoms-deep craters to fill up, like natural-made landfills.