Because the moon has been frequented by man on a lot of occasions, it is only expected that he would be leaving his mark on it. One undeniable mark is trash. It is a bit astonishing that the trash on the moon already amounts to at least 181,000 kilograms or 400,000 lbs. on Earth. Some of the trash left there are lunar orbiters, one falcon feather, one flag kit, one hammer, one gold olive branch, five moon rangers, and heavy artifacts. Despite the clutter, researchers study these items to see how vacuum and radiation have deteriorated the materials over time. The objects also have an archeological value.
For more, see the full Space.com article. It’s a good one!