Draw tool spray inoperative

I’m trying to use the Draw Tool to get rid of a noise of about 1000 samples in a quiet passage. It occupies about 50 peaks and troughs. The manual says:

Smooth the vertical disparity in a group of samples by holding down Alt (or Ctrl + Alt on Linux). This changes the mouse pointer to a brush (or spray can on Linux). Position the pointer halfway along the group of samples then click repeatedly to progressively smooth the group.

When I select the passage, zoom in to sample level, select Draw, and click Ctrl+Alt+click half-way through the sample, the spraycan cursor appears OK, but repeated clicking does nothing: none of the samples moves; there is no change. I was expecting the samples to be smoothed towards the 0.0 line.

What am I doing wrong?

Probably nothing.

The spray can tool looks at a very localised region of samples, and smooths that region, so it is effective at smoothing small clicks and crackles, but if the waveform changes more slowly it has little or no effect.

Please post a short section (just a few seconds) of the audio in WAV format so that we can see what you are trying to fix. There’s probably a better way than the spray can tool (See: https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1)

I had already used Noise Reduction (great) and tried Click Removal (helped).

Here we go…

It’s probably not possible to remove that noise entirely, but it can be reduced.
Try the “Pop Mute” plug-in: https://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Pop_Mute
It’s a “Nyquist plug-in”. Installation instructions here: https://manual.audacityteam.org/man/installing_effect_generator_and_analyzer_plug_ins_on_linux.html#nyquist_install

Great stuff, thanks.