Noise Reduction is designed for steady background noises such as minor hum or microphone hiss. It doesn’t do so well with sporadic noises such as popping or clicking, if for no other good reason, it’s impossible to get a sample.
Noise Reduction works by being exposed to a clean sample of the sound. You let it “sniff” the noise. Then like a good bloodhound, you turn it loose on the show and it goes charging down chewing on the noise leaving the show alone. Constantly changing noises mess up the sample step.
Please note that if you can’t get a clean sample, that’s deadly, too. If the noise is constantly combined with other sounds, you’re dead.
You might find some of the vinyl click and pop tools valuable.
Getting a clean sample is a must. i usually have pretty good results if there is a second or two of the noise i want to remove at the beginning or end of a track. Highlight just the noise and get sample then can remove by running noise reduction at highest settings when only noise is selected/highlighted. only use highest settings when noise only is selected. you should be left with silence in place of the noise. for the full track, select the entire track and run noise reduction again, this time change settings to 12, 6, 3 as seen in image attached. works best for steady noise that is throughout recording such as fans, hum, buzz, etc. for full track method you still need a good sample of just the noise prior to running.