Just leave it. Either they do something in the background. Then you'll get issues when they're missing, and you'll never know which package is missing for what.
Or they don't do anything, then they just take up a few MB of disk space.

"Cleaning up" is the most sure-fire way to destroy your OS, and absolutely not worth anyone's time. Trust me, I've made that mistake multiple times.

Let's just say my last attempt at automated cleanup didn't go well (my desktop disappeared!) Now I’m a collector and keep everything.

apt autoremove will do it. Just double check what it's removing for obvious problems.

That's because a lot of them are dependencies for the packages you actually want to use, and those needed for the system to work as designed.

EDIT: More information provided. I disagree with the upvoted comment implying you should leave your system alone because you might break something. You're using Arch, and part of the reason to use Arch is understanding how you built and maintain your system. Understanding how to inspect your system and perform proper maintenance is a crucial part of that. Read and think carefully before taking any actions and make sure any important information is backed up before taking major actions. Without throwing too much further shade, I find it disappointing so many in the community would take that stance and discourage you from pursuing this further.

When I switched to Arch, I started a notebook in Obsidian with a bunch of different information in it, I have a section devoted to Maintenance. Here are a few things I've put in there:

Clean package cache with paccache: https://ostechnix.com/recommended-way-clean-package-cache-arch-linux/

Clean orphaned dependencies: sudo pacman -Rs $(pacman -Qtdq)

• https://man.archlinux.org/man/pacman.8.en
• Qtdg, Q (Query) t (unrequired) d (dependencies) g (groups)
• Rs, R (Remove) s (recursive)

Additionally, you can run pacman -Qe to list the packages you yourself have explicitly installed with pacman, or pacman -Qdt to list the packages that are dependencies of other packages. Use pacman -Qm to list packages not found in the official repositories (i.e., things installed through yay). This will allow you to review packages you may have explicitly installed in the past for some reason, but now find you no longer need.

For yay, I'm unsure if I should be using -Yc, -Sc, or -Scc. If anyone has more info with that, I'd appreciate it.

For flatpak: flatpak uninstall --unused

And for journals: journalctl --vacuum-time 7days

That's most of the "automatic" stuff, cruft that can be cleaned out with little to no consequence. Other than that, you'll just have to manually review what you have on your system.

If anyone has other commands or comments on the ones I provided, I'd be happy to accept further advice here as well 😃

For anyone reading this on a Debian-based system, you can get a good start without risking removing anything important like this:

1. Run apt-mark showmanual, and copy any package names you don't think you need into a list.
2. Run apt-mark auto <pkg1> <pkg2> ...
3. Run apt autoremove

These are just dependencies for your packages. However, Arch doesn't automatically clean the downloaded files after installation so that ends up taking space. On my Dell laptop that has only a 64 GB eMMC, the installation package files took and whopping 5 GB of space, sitting there doing nothing. I nuked them (it didn't remove the installed apps and libs, only the already used package files). Run: sudo pacman -Scc

You can run pacman -Qe to list explicitly installed packages, beware of packages you may have installed manually as optional dependencies of other packages.

Assuming you are using something Debian based, you can use:

apt purge (package name)

Followed by:

apt autoremove