I generally don’t like automated cleanup tools. It’s rare that they are even necessary. OS X is designed to clean up after itself. Since most of these applications require administrative permissions, If I do need an automated tool, I prefer open source software. With open source software you can review the code before running it. Even if you can’t read the code, it’s unlikely that something intentionally malicious would be in the code since other people usually review the code.

Always make sure you have a verified backup before performing any of the actions below.

Common things that automated cleanup tools do

Removing Applications

Removing applications is as simple as moving them to trash. Or if the application came with an uninstaller, use that. Applications will sometimes leave behind some settings. Usually this is intentional; so you don’t lose settings when reinstalling (like licenses). To remove Application preferences, in Finder click Go > Go to Folder...command + shift + g and type or paste one of these paths:

System:
/Library/Preferences/

User:
~/Library/Preferences/
~/Library/Containers/

Before permanently removing a preference, archive the file (don’t forget to rename the archive) in the folder you are removing it from. Or on the desktop, just add the path to the name so you know where it goes. Then test the system. If everything functions as expected, then you can remove the archive to recover the space.

Removing Caches

Deleting caches will negatively effect performance and should only be done when there is already an issue. And then, only for the specific application that has problems. Removing caches will not save any space since the OS is just going to rebuild them. This is where you can find the caches:

System: /Library/Caches/
User: ~/Library/Caches/

Restart to complete the cache cleanup.

Removing Login Items

You can remove your Login Items by going to System Preferences > Users & Groups select your name, then click Login Items on the right. Select any items you want to remove and then click the - at the bottom. Applications put their login settings here:

System: /Library/LaunchAgents/
User: ~/Library/LaunchAgents/

Removing Startup Items

Application startup settings can be found here:

System: /Library/LaunchDaemons/
User: ~/Library/LaunchDaemons/

Removing Translations

This is the one exception to automated tools; because it would take a ridiculously long time to do it manually.

You can recover a lot of space by removing the translations for applications on your Mac that you won’t use. Keep in mind that you will have to reinstall the applications and or OS if you need the language later. I would suggest Monolingual for removing languages;  it’s open source.

Application Maintenance

(coming soon)