You can't really change the orbit of spent stages from rockets
Doing it robotically would be expensive and time consuming but it would be a guarantee of the junk being gone.
Lasers might work for smaller debris if you can get lasers onto already orbiting stations specifically for that purpose but larger objects would take forever to destroy that way, but I could be wrong because I don't know much about lasers
Lasers are very energy inefficient, and the risk of reflections would be high.
better off shooting a netgun with small spheres containing a retracting cable strung through the net's periphery, attached at the corners (or equidistantly around the periphery) of the net would probably work better, but shooting the net would impose a thrust against the launching vehicle. it would need a good suply of station keeping propellant.
since there is no air up there to speak of, drag isnt as much of a concern, so shooting the net fuly deployed (open), with very tiny netting would work just fine. when the net hits the target debris field, the little spheres on the periphery engage, and sinch up the cable strung between them, closing up the net like a sack. now instead of hundreds of small objects, you have a large aggregated one that you can more easily deorbit.