Hi,

Noise is often less louder then the actual sound.
If this is the case you can take the sound
through a compressor and select an option called 'hard noise gate'.
If your compressor doesn't has this option
you can set it manually:
Attack:1ms
Release:450ms
Threshold: approx: -30db
ratio: 1:1
If the noise stays then try to raise the threshold little by little.
Good luck