$ brew options --command cleanup --compact
--debug --dry-run --prune --prune-prefix --verbose -s

$ brew options --command cleanup
--debug
	Display any debugging information.
--dry-run
	Show what would be removed, but do not actually remove anything.
--prune
	Remove all cache files older than specified <days>.
--prune-prefix
	Only prune the symlinks and directories from the prefix and remove no other files.
--verbose
	Make some output more verbose.
-s
	Scrub the cache, including downloads for even the latest versions. Note downloads for any installed formulae or casks will still not be deleted. If you want to delete those too: `rm -rf "$(brew --cache)"`

$ brew options --command update
--debug
	Display a trace of all shell commands as they are executed.
--force
	Always do a slower, full update check (even if unnecessary).
--help
	Show this message.
--merge
	Use `git merge` to apply updates (rather than `git rebase`).
--verbose
	Print the directories checked and `git` operations performed.