Remove brew completely from my system
You can use this to check if it left anything behind in one of the system directories:
https://github.com/shundhammer/qdirstat/blob/master/doc/Unpkg-View.md
You'll still have to carefully go through your home directory to check if it left anything behind there.
I installed brew with the homebrew install script which installs in /home/linuxbrew/.
I just found that one folder, where it resided, I removed that, and freed up 3GB:
sudo rm /home/linuxbrew/ -Rf
Check for remaining brew components with
locate brew -e|egrep -iv '(hebrew|ansible)'|grep brew