If anyone says Karaoke, I'm gonna freakin' hurl !
Best way to remove vocals from a mix is to go back to the original tracking and remove it.
If there was any serious bleed, you need a vocal booth (their raison d'^ etre) or better isolation.
Anything else is just fun, but there isn't anything wrong with that,
just as long as I don't have to hang around and listen to it.