Artifacts: These typically consist of random bursts of very short tones at random frequencies, sometimes called “musical noise”, “bird song” or “tinkly-bells”. These may be visible in Spectrogram view.
I’m not quite sure what the real question is, but “random bursts” and Effect > Noise Reduction are really, really, different. Noise Reduction tends to be handy for long-form noises that hang around such as power line hum, fan noises, or microphone hiss. Not Random Bursts.
Spectrogram view is pitch or frequency up and down, time left to right and color is loudness. So if you have a white blob at five minutes about half-way up the display, then you have a very loud burst of sound at about 4000Hz (fingernails on blackboard—baby screaming on a jet) occurring five minutes into the show.
I’ve never done it, but I know you can actually edit in spectrogram view by erasing colors.