Download and install the Audacity program for audio file editing. Click on the download icon and save the file on your computer. Run the file and complete the prompts to install Audacity on your computer. This audio editing program will allow you to remove the vocals on most commercial audio tracks.
Download and install the Canter Pan Remover plug-in for Audacity. Copy or drag the file into the plug-ins directory of the Audacity folder. This will automate the process of removing the vocals by removing the audio that is centered in the stereo field. Most vocals lie in this area of the audio spectrum on commercial recordings.
Open the Audacity program and wait for it to load. This will give you access to all of the built-in tools as well as any plug-ins you have added to the plug-ins folder. Open the mp3 or .wav file you wish to remove the vocals from. Play the file to make sure that it is an audio file and that the vocals are currently intact before proceeding.
Open the "Effects" menu located on the menu bar above the main window. Apply the "Center Pan Remover Effect" to the audio track. This will invert the left and right tracks and eliminate the center channel, thus removing any vocals in that audio space. After the computer has processed the effect, play the song and listen back to make sure that the vocals have been removed.
Experiment with the slider on the Center Pan Remover controls to keep as much of the audio intact while also removing the vocals. This will allow you to select frequencies to remove rather than an entire channel. Select a maximum and minimum frequency in order to help eliminate the audio above and below these frequencies.