Trimming
You can trim the start and end of a song by editing the Trim values. Show the Trim Start/End columns by context-clicking on the sort column headers, then pick the Trim value you want to edit (start or end). Now, you can simply edit the value for the song, or you can play the song and pause it at the moment you want, then pick Control->Set Trim Value, and it will set the trim value for that song. Next time you go to play that song, it will start at the Trim Start time, and end at the Trim End time. To remove a trim value, just edit the value and delete the text.
Trim values are in CDDA timecode, that is: minutes (base 60):seconds (60):frames (74).records (4), you may edit typing timecode eg: "1:20" is one minute twenty seconds, or just "5" is five seconds, or 4:35:62.2 is 4 minutes, 35 seconds, 62 frames (62/75ths of a second) and 2 "records" (2/4 of a "frame" or 2/300ths of a second). Yeah, weird, i know.