[redsky17]

You can generally do this pretty closely digitally by taking the left and right channels of a stereo track and inverting the phase on one of them. Since the vocals are usually panned center (as you said), the inverted phase ends up destructively cancelling them. Depending on how the instrumentation was mixed, usually the instruments are left pretty in-tact.

[codedokode]

Usually the track sounds awful. For example, the bass can go away with the vocals, instruments' timbre change etc.

[vonseel]

Makes sense since panning bass would be an odd thing to do.