Space Junk:

There is no easy answer on space junk, since all of the items would have to be collected somehow. The majority of space junk lacks and propulsion system that would allow the object to reduce it's orbital velocity so that it would fall and burn up in a controlled reentry into the atmosphere.

One recent suggestion almost made sense, a giant stickyball type of spacecraft that would sweep entire areas of junk and then deorbit. But the drawback is that the big stickyball would also sweep up active satellites that were still in use.

Moon Resources:

As for resources on the Moon, any resources missing would have to be delivered. If there is ice frozen in the crater shadows at the poles, it would make human settlement much easier. If there is no water there, it has to be brought from Earth or manufactured on site with atomic oxygen and hydrogen.

It may take less energy to mine the asteriods for material than to lift it out of the Earth's gravity well. If we could capture a small comet, that would provide a lot of water, too. We could attach an ion propulsion module on it and crash it on the moon.