Ubuntu boot partition too small on System76

My boot partition is too small on my System76 Kudu and I encrypted the drive.. so I guess I am stuck with it until I want to start over.

When it gets filled up, the advice to use the following never seems to clear enough space.

sudo apt-get autoclean
sudo apt-get autoremove

So I have found that I have to use

sudo apt-get remove --purge $(dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d')

Which gets rid of all the unused kernels.