You can cleanup your Homebrew cache

If you work on a Mac, you probably know Homebrew. It's a package manager for MacOS (née Mac OS X). I've been using Homebrew for several years now, on different machines. My laptop has a brew "history" (that's no real command…) of a few years and many software packages' versions. Some weeks ago I looked through the Homebrew man pages and discovered:
brew cleanup.

cleanup [--prune=days] [--dry-run] [-s] [formulae]  
              For  all installed or specific formulae, remove any older versions from the cellar. In addition, old downloads from the Homebrew
              download-cache are deleted.

              If --prune=days is specified, remove all cache files older than days.

              If --dry-run or -n is passed, show what would be removed, but do not actually remove anything.

              If -s is passed, scrubs the cache, removing downloads for even the latest versions of formulae. Note downloads for any installed
              formulae will still not be deleted. If you want to delete those too: rm -rf $(brew --cache)

As the name implies, it cleans your Homebrew cache of older versions and older downloaded files. I do this regularely (relatively). This is what it looked like for me, just this morning.

~ % brew cleanup
Removing: /usr/local/Cellar/cmake/3.6.3... (2,029 files, 27.8M)  
Removing: /usr/local/Cellar/cmake/3.7.0... (2,140 files, 29M)  
Removing: /usr/local/Cellar/git/2.10.2... (1,445 files, 31.8M)  
Removing: /usr/local/Cellar/heroku/3.43.13... (994 files, 6.2M)  
Removing: /usr/local/Cellar/imagemagick/6.9.6-3... (1,465 files, 22.5M)  
Removing: /usr/local/Cellar/imagemagick/6.9.6-5... (1,467 files, 22.1M)  
Removing: /usr/local/Cellar/libtiff/4.0.6_3... (262 files, 3.4M)  
Removing: /usr/local/Cellar/node/7.1.0... (3,884 files, 45.4M)  
Removing: /usr/local/Cellar/postgresql/9.5.5... (3,154 files, 35.1M)  
Removing: /usr/local/Cellar/python3/3.5.2_1... (3,607 files, 54.1M)  
Removing: /usr/local/Cellar/rbenv/1.0.0... (36 files, 61.9K)  
Removing: /usr/local/Cellar/readline/7.0... (45 files, 2M)  
Removing: /usr/local/Cellar/ruby/2.3.1_2... (1,261 files, 18.8M)  
Removing: /usr/local/Cellar/ruby/2.3.2... (1,263 files, 18.9M)  
Removing: /usr/local/Cellar/ruby-build/20160913... (304 files, 165K)  
Removing: /usr/local/Cellar/ruby-build/20161115... (320 files, 171.6K)  
Removing: /usr/local/Cellar/sqlite/3.15.1... (11 files, 2.9M)  
Removing: /usr/local/Cellar/the_silver_searcher/0.33.0... (8 files, 106.4K)  
Removing: /usr/local/Cellar/vim/8.0.0071... (1,710 files, 23.3M)  
Removing: /usr/local/Cellar/vim/8.0.0094... (1,712 files, 23.3M)  
Removing: /usr/local/Cellar/vim/8.0.0104... (1,712 files, 23.3M)  
Removing: /usr/local/Cellar/vim/8.0.0118... (1,713 files, 23.3M)  
Removing: /usr/local/Cellar/yarn/0.17.3... (5,645 files, 18.2M)  
Removing: /usr/local/Cellar/yarn/0.17.6... (5,637 files, 18.2M)  
Removing: /usr/local/Cellar/yarn/0.17.8... (5,637 files, 18.2M)  
Removing: /usr/local/Cellar/yarn/0.17.9... (5,639 files, 18.2M)  
Removing: /Users/holger/Library/Caches/Homebrew/cmake-3.6.3.sierra.bottle.tar.gz... (10M)  
Removing: /Users/holger/Library/Caches/Homebrew/cmake-3.7.0.sierra.bottle.tar.gz... (10.6M)  
Removing: /Users/holger/Library/Caches/Homebrew/git-2.10.2.sierra.bottle.1.tar.gz... (11.7M)  
Removing: /Users/holger/Library/Caches/Homebrew/heroku-3.43.13.tgz... (1.7M)  
Removing: /Users/holger/Library/Caches/Homebrew/imagemagick-6.9.6-3.sierra.bottle.tar.gz... (8.5M)  
Removing: /Users/holger/Library/Caches/Homebrew/imagemagick-6.9.6-5.sierra.bottle.tar.gz... (8.4M)  
Removing: /Users/holger/Library/Caches/Homebrew/libtiff-4.0.6_3.sierra.bottle.tar.gz... (1M)  
Removing: /Users/holger/Library/Caches/Homebrew/mysql-5.7.16.sierra.bottle.tar.gz... (92.3M)  
Removing: /Users/holger/Library/Caches/Homebrew/node-7.1.0.sierra.bottle.tar.gz... (12.6M)  
Removing: /Users/holger/Library/Caches/Homebrew/node-7.2.0.sierra.bottle.tar.gz... (12.6M)  
Removing: /Users/holger/Library/Caches/Homebrew/postgresql-9.5.5.sierra.bottle.tar.gz... (10.0M)  
Removing: /Users/holger/Library/Caches/Homebrew/ruby-2.3.2.sierra.bottle.tar.gz... (6.7M)  
Removing: /Users/holger/Library/Caches/Homebrew/ruby-build-20161115.tar.gz... (51.1K)  
Removing: /Users/holger/Library/Caches/Homebrew/sqlite-3.15.1.sierra.bottle.tar.gz... (1.4M)  
Removing: /Users/holger/Library/Caches/Homebrew/vim-8.0.0071.sierra.bottle.tar.gz... (7.9M)  
Removing: /Users/holger/Library/Caches/Homebrew/vim-8.0.0094.sierra.bottle.tar.gz... (7.9M)  
Removing: /Users/holger/Library/Caches/Homebrew/vim-8.0.0104.sierra.bottle.tar.gz... (7.9M)  
Removing: /Users/holger/Library/Caches/Homebrew/vim-8.0.0118.sierra.bottle.tar.gz... (7.9M)  
Removing: /Users/holger/Library/Caches/Homebrew/yarn-0.17.3.sierra.bottle.tar.gz... (4.2M)  
Removing: /Users/holger/Library/Caches/Homebrew/yarn-0.17.6.sierra.bottle.tar.gz... (4.2M)  
Removing: /Users/holger/Library/Caches/Homebrew/yarn-0.17.8.sierra.bottle.tar.gz... (4.2M)  
Removing: /Users/holger/Library/Caches/Homebrew/yarn-0.17.9.sierra.bottle.tar.gz... (4.2M)  
Removing: /Users/holger/Library/Logs/Homebrew/cask... (68B)  
Removing: /Users/holger/Library/Logs/Homebrew/couchdb... (68B)  
Removing: /Users/holger/Library/Logs/Homebrew/fish... (68B)  
Removing: /Users/holger/Library/Logs/Homebrew/glib... (68B)  
Removing: /Users/holger/Library/Logs/Homebrew/mysql... (68B)  
Removing: /Users/holger/Library/Logs/Homebrew/node... (68B)  
==> This operation has freed approximately 722.5M of disk space.

722.5MB in just a few days. I am curious how many megabytes it will free up for you. Please let me know on Twitter