Linux systemd: remove slice

Out of curiosity, is there any way to remove a systemd slice that you’ve created? I’m running on Fedora 28 with systemd-238-9 and kernel 4.17.12-200.fc28.x86_64 .

I performed:

systemd-run --unit=toptest --slice=test top -b

And after the top had exited, I can see my slice:

systemctl -t slice --all

But I can’t remove it. I have tried

systemctl stop test.slice
systemctl kill test.slice
systemctl unload test.slice

(the latter gives an “unknown operation”), but still my slice lives in that list.

Thanks.

systemctl kill  test.slice
Failed to kill unit test.slice: Unit test.slice not loaded.