Start Audacity and open the audio file that you would like to edit.
Find the "effect" menu located at the top of the screen.
Select "click removal" from the effects menu. Use the preview option to determine if the amount of click removal is appropriate. If the preview sounds like too much audio has been affected, lower the sliders on the "max spike width" option until the preview sounds appropriate. Click OK. This option will remove clicks and pops in the music.
Find the "noise removal" option under the effects menu. When you select it, a dialog box will open. Click "get noise profile." The system will analyze the audio and get a sample of the piece to determine which noise to remove and then remove the noise. Don't change any of the default settings.
Select "noise removal" again. This time, select OK at the bottom of the screen. The composition will be edited for noise. If too much noise is removed press CTRL-Z to undo the changes and then change the "noise reduction" option in the "noise removal" dialog box. If too much noise has been removed, lower the "noise reduction"; if too little noise is removed, raise the level of "noise reduction."
Select the "normalize" option under the effect menu. This option will restore the audio to the maximum volume possible without causing distortion. This effect is necessary as the previous edits will have reduced the overall volume of the music.