Astroscale is trying to push a standardized docking adapter for that purpose and Northrop Grumman has a vehicle that was able to dock to the engine of another s

Astroscale is trying to push a standardized docking adapter for that purpose and Northrop Grumman has a vehicle that was able to dock to the engine of another satellite to serve as a life extension vehicle, so assuming that can be easily adapted to other satellites, they too can provide a deorbiting service. Clearing out several satellites with one vehicle is not practical though, would need too much fuel. At best one might launch several such vehicles on one launch, or if orbital fuel depots really take off soon, it may be possible to have depots in convenient locations such that deorbiting vehicles can always make a relatively cheap visit to a depot to refuel and wait for another deorbiting target. In such a setup the deorbiter would just lower one end of the orbit to speed up decay rather than dragging it all the way down to Earth.