Remove a specific snap package

When I run df -h I see that I have several /snap entries with similar names and sizes. I've edited and rearranged the output, so that similar names all appear together (see below).

I am guessing that I should be able to remove (for example) the earlier instance of Gimp: /snap/gimp/367. This article tells me how to reduce a named snap package, but I haven't found how to remove just one of two packages with the same name.

Also, which of the core... packages do I really need?

Thanks in advance for any help with this.

/snap/audacity/857           /dev/loop17     188M  188M     0 100% 
/snap/chromium-ffmpeg/17     /dev/loop11      33M   33M     0 100% 
/snap/core/11167             /dev/loop10     100M  100M     0 100% 
/snap/core/11187             /dev/loop19     100M  100M     0 100% 
/snap/core18/2066            /dev/loop13      56M   56M     0 100% 
/snap/core18/2074            /dev/loop6       56M   56M     0 100% 
/snap/core20/1026            /dev/loop23      62M   62M     0 100% 
/snap/core20/975             /dev/loop14      62M   62M     0 100% 
/snap/gimp/367               /dev/loop22     269M  269M     0 100% 
/snap/gimp/372               /dev/loop21     277M  277M     0 100% 
/snap/gnome-3-28-1804/145    /dev/loop4      163M  163M     0 100% 
/snap/gnome-3-38-2004/39     /dev/loop16     244M  244M     0 100% 
/snap/gtk-common-themes/1514 /dev/loop9       65M   65M     0 100% 
/snap/gtk-common-themes/1515 /dev/loop8       66M   66M     0 100% 
/snap/gtk2-common-themes/13  /dev/loop0      256K  256K     0 100% 
/snap/heroku/4048            /dev/loop2       27M   27M     0 100% 
/snap/opera/128              /dev/loop15     151M  151M     0 100% 
/snap/opera/130              /dev/loop1      151M  151M     0 100% 
/snap/postman/133            /dev/loop18     176M  176M     0 100% 
/snap/skype/173              /dev/loop12     135M  135M     0 100% 
/snap/skype/176              /dev/loop5      136M  136M     0 100% 
/snap/snapd/12057            /dev/loop3       33M   33M     0 100% 
/snap/snapd/12159            /dev/loop20      33M   33M     0 100% 
/snap/telegram-desktop/2637  /dev/loop7      302M  302M     0 100%

Do not remove the core packages. The other snaps depend on them.

If you want to remove gimp altogether, you can remove it with

sudo snap remove gimp

If you want to remove an old, unused version of gimp or any other package, have a look at this answer.

List your installed snaps with the command

snap list --all

The output displays, among others, a "Name" (first column) and a "Rev" (revisions, third column) column. Remove a specific revision with a command such as

snap remove <Name> --revision <Rev>

substituting and with what you saw in the output.