When I was little trying to play along with Hendrix and SRV it was pretty easy to get backing tracks by unplugging one of your speakers since a lot of older recordings sent most of the guitar to one channel or another.

_________________
Custom Shop '59 Strat with John Cruz Master Design Pickups
Vibro King
Fulltone Clyde>Deja-Vibe>TS-808>TS-9>Boss Tuner

You can also split the stereo track into its left and right channels, make both mono, invert all (or a selected part) of one of them, and play back the result.

This removes everything panned in the center, not just vocals. In pop music this can mean removing the bass and rhythm parts. Removal of the vocals is normally incomplete and will leave artifacts behind, especially where reverberation (echo) is used, and where there are backing vocals.

Sometimes certain minor strands of the instrumentals are exposed which are completely covered in the uninverted mix. This technique works particularly poorly with tracks where a lot of stereo reverberation has been applied, as this spreads each sound source, and makes them very hard to extract from each other.

_________________
Being able to play and enjoy music is a gift that's often taken for granted.

Don't leave home without it!