Leonardo said:

Okay, these are the settings I used with this particular clip. I would recommend, however, fiddling with it on a case by case basis, as different audio could demand lighter or heavier correction.

I highlighted the waveform, opened the "Remove Hum" module.

Clicked on "Frequency Type", selected Free. Linear phase, high pass, low pass boxes are all unchecked. Harmonics is set to 8. Harmonic slope is set to "0".

Linking Type: All. Filter DC Offset is checked.

Click on the "Learn" button, select "Process".

Voila. :)

Thank you very much! will definitely hang on to this info just in case I run into something like this.