Satellites in low earth orbit (LEO) de-orbit themselves within a fairly short time after they run out of fuel keeping them on station. They lose altitude constantly due to air drag (there is a very tiny amount of air in LEO). LEO space junk solves itself.
The type of space junk that can actually be an issue is in other useful orbits, such as the geostationary orbit. Satellites there are expected to move themselves into graveyard orbits at the end of their life so they are out of the way.