Some things come to mind regarding space junk. Firstly, I think the Space Shuttle could have been put to good use collecting space junk. Secondly, could all this space junk be sent to the moon, for possible future use at a lunar outpost?

It seems to me that some modified version of a Space Shuttle, redesigned just for orbital and trans-lunar injection, without any planned Earth re-entry, could be used for this purpose. Sure there's the question of fuel to address, but I suspect something could be devised in conjunction with a lunar outpost.