Audacity: Can I remove the vocals from a recording to make a Karaoke track?

Today I was asked to remove the voice from a song (for a kid's Christmas event). I already knew that it is simply impossible to achieve in a general-purpose tool - it depends on the frequency arrangements of the voice parts of the song. However, I found a little program (I've used before) called Audacity that is able to help us with this task. the authors have even written a small page with the necessary steps for a specific (albeit common) case:

1. Import your stereo file into Audacity.
2. Open the track menu (click the arrow next to the track title), and choose “Split Stereo Track.”
3. Select the lower track (the right channel) by clicking it in the area around the mute/solo buttons.
4. Choose “Invert” from the Effects menu. 5. Using the track menus, change each track to “Mono.”

[See the full article in Audacity: Can I remove the vocals from a recording to make a Karaoke track?]