pasta cleanup / boot Linux Mint 19

Question

Usando o Linux Mint 19 MATE de 64 bits. Encontrado Como limpar o diretório / boot no LINUX Mint?

-rw-r--r--  1 root root  1536934 april   24 07:56 abi-4.15.0-20-generic
-rw-r--r--  1 root root  1537161 june 12 19:09 abi-4.15.0-24-generic
-rw-r--r--  1 root root  1537161 july 17 11:57 abi-4.15.0-29-generic
-rw-r--r--  1 root root   216807 april   24 07:56 config-4.15.0-20-generic
-rw-r--r--  1 root root   216807 june 12 19:09 config-4.15.0-24-generic
-rw-r--r--  1 root root   216807 july 17 11:57 config-4.15.0-29-generic
drwxr-xr-x  5 root root     4096 july 24 00:00 grub/
-rw-r--r--  1 root root 58004211 july 23 22:34 initrd.img-4.15.0-29-generic
-rw-r--r--  1 root root   182704 january  28  2016 memtest86+.bin
-rw-r--r--  1 root root   184380 january  28  2016 memtest86+.elf
-rw-r--r--  1 root root   184840 january  28  2016 memtest86+_multiboot.bin
-rw-r--r--  1 root root        0 april   24 07:56 retpoline-4.15.0-20-generic
-rw-r--r--  1 root root        0 june 12 19:09 retpoline-4.15.0-24-generic
-rw-r--r--  1 root root        0 july 17 11:57 retpoline-4.15.0-29-generic
-rw-------  1 root root  4038188 april   24 07:56 System.map-4.15.0-20-generic
-rw-------  1 root root  4040379 june 12 19:09 System.map-4.15.0-24-generic
-rw-------  1 root root  4040379 july 17 11:57 System.map-4.15.0-29-generic
-rw-------  1 root root  8257272 july 17 18:26 vmlinuz-4.15.0-29-generic

kernel (s) instalado (s):

# dpkg -l | grep linux-image
ii  linux-image-4.15.0-29-generic              4.15.0-29.31                        amd64        Signed kernel image generic
ii  linux-image-generic                        4.15.0.29.31                        amd64        Generic Linux kernel image
# dpkg -l | grep linux-header
ii  linux-headers-4.15.0-29                    4.15.0-29.31                        all          Header files related to Linux kernel version 4.15.0
ii  linux-headers-4.15.0-29-generic            4.15.0-29.31                        amd64        Linux kernel headers for version 4.15.0 on 64 bit x86 SMP
ii  linux-headers-generic                      4.15.0.29.31                        amd64        Generic Linux kernel headers

Alguma idéia para remover kernels antigos para que esses arquivos de configuração também sejam removidos? Eu removi kernels antigos com purga apt ... mas não ajudou.