Re: [Trisquel-users] Old Kernels

[davesamcdxv]

(As I've said above) Unlike (most) other pacakges, different versions of the  
kernel are provided in different packages, and because of that don't  
overwrite each other. To remove them you've got to manually do so by locating  
their packages.

Or if they're installed only because one of the "linux" meta packages dragged  
them, This should do:
 sudo apt-get  autoremove --purge