Delete gray matter on spectrogram

I am trying to connect multiple tracks from a performance track cd. The cd will have one song using 6 tracks, when played on cd player they play continuous without breaking between the tracks. However, I would like to connect them so I can have it as 1 mp3 instead of needing a cd player. I have the tracks in audacity, I have tried several ways and still hear like a skip, when I zoom in, in the spectrogram mode of the track there is a grey area, but I can’t delete or cut it out, it just moves instead of going away.

Windows 10

Audacity 2.1.2

The blank grey area on the spectrogram corresponds with a boundary-marker.
Removing the boundary-marker will get rid of the blank gray area, but it will not change the sound: it will not cure the skip.
A crossfade may be the answer to blending your tracks …

Some CD ripping software (including [u]EAC[/u]) can optionally rip a CD “image” as one continuous WAV or MP3 file.

Note - With one continuous file you can’t have track markers.