Right-click the audio track of original clip in the bin, or a clip on the audio track, and Save Audio Clip As New File.
It should land in the MUSIC folder on the PC. Open it with Wavepad, which has greater editing capability. Experiment with the many features. Try the equalizer and pass filters, which are also available in VP to a lesser degree.
When satisfied, save the file and bring it back into VP as another audio track. Mute the original track.