"Sampling the sound" likely will pick up parts of other low frequencies that aren't really noise, so if you remove what looks like your sample you'll lose more than you want to.

I'm not familiar with the program, but if it has a specific "60 Hz remover" you're likely to have better results from using it. The 60 Hz power frequency nearly always is very accurate and stable, so a "narrow band" removal should be quite accurate.

(But I'm just guessing. One of our experts can probably be more specific.)

John