 If the automatic filtering software is getting every last click, chances are good that it could also be filtering some percussion instruments.After an automatic click filtering, it is reasonable to expect a few clicks to be left over, and these must be removed manually by isolating them one-by-one in the waveform.These residual clicks may then be corrected by attenuation (reducing or muting the volume of the anomaly), interpolation (replacing the waveform "spike" with a less offensive section, either a straight line—linear interpolation—or a calculated facsimile deduced from what the wave looks like on either side); "substitution" (replacing a damaged waveform segment with a similar section from elsewhere); "channel substitution" (where damage occurring in only one channel of a stereo waveform is replaced by a similar good segment in the other channel); and "simple deletion", which is usually not noticeable for small samples.