According to the manual and the videos on Youtube, in 6x6 mode select the track, double click the right footswitch to mute the track, then hold down the right footswitch to clear the track. Unfortunately this doesn’t work, and so I think there’s a bug that needs to be fixed.
At the moment I’ve been able to create backing for a couple of songs, but if I make a mistake then I have to clear the entire song and start over from scratch.
In one instance I found that attempting to clear the track, then switching the machine off and on again left me with a cleared track. This might be an option until the bug is fixed.
I get that having purchased one of the first 100 Aeros Loopers I’m really a beta tester but I’m looking forward to this bug being fixed. It limits what can be done with the Aeros.