загрузочному разделу не хватает места, могу ли я избавиться от неиспользуемого материала?

У меня есть раздел 512MiB, который я назначил на /boot, но LinuxMint продолжает добавлять туда много материала при обновлениях и теперь жалуется на использование диска.

A df -h читает:

Filesystem      Size  Used Avail Use% Mounted on 
udev            7,8G  0  7,8G   0% /dev 
tmpfs           1,6G  9,5M  1,6G   1% /run 
/dev/sdb5 48G   13G   35G  27% / 
tmpfs           7,8G  326M  7,5G   5% /dev/shm 
tmpfs           5,0M  4,0K  5,0M   1% /run/lock     tmpfs           7,8G   0  7,8G   0% /sys/fs/cgroup 
/dev/sdb7       183G   59G  125G  33% /home 
/dev/sdb1       484M  473M   12M  98% /boot 
cgmfs           100K 0  100K   0% /run/cgmanager/fs 
tmpfs           1,6G   60K  1,6G   1% /run/user/1000 

Как я могу очистить неиспользуемые ядра и сохранить /boot чистым?

EDIT

# apt-get autoremove
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 26 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up linux-image-extra-4.4.0-45-generic (4.4.0-45.66) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.4.0-45-generic /boot/vmlinuz-4.4.0-45-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.4.0-45-generic /boot/vmlinuz-4.4.0-45-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.4.0-45-generic /boot/vmlinuz-4.4.0-45-generic
update-initramfs: Generating /boot/initrd.img-4.4.0-45-generic
Warning: No support for locale: en_US.utf8

gzip: stdout: No space left on device
E: mkinitramfs failure cpio 141 gzip 1
update-initramfs: failed for /boot/initrd.img-4.4.0-45-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-extra-4.4.0-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 linux-image-extra-4.4.0-45-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)