Is the "Cellar" folder only used for Homebrew? If I am not using Homebrew, I can safely remove it?
The script for uninstalling Homebrew removes it completely, so it's probably safe to remove it.
How do I uninstall Homebrew?
If you installed to
/usr/localthen you can use the script in this gist to uninstall — it will only remove Homebrew and the stuff Homebrew installed leaving anything else in /usr/local alone.
Provided you haven’t put anything else in Homebrew’s prefix (
brew --prefix), you can generally just
rm -rfthat directory. This is because Homebrew won’t touch files outside its prefix.