How to clear system storage?

Yes, there is one way: keep a watch on your hard drive space at all times. The drive isn’t just “storage”, it contains your OS and vital system files which are needed for the computer to work. They were require a minimum of empty space to function properly - at least 10 - 15 GB of empty space at all times. If you fill it up completely, the computer will stop functioning.

Get an external drive and move your space hogging files to it, then delete them from your internal. Usually that is movies, videos, photos, etc. For Big Sur, you need a minimum of 35.5 GB of empty space plus the aforementioned 10 - 15 GB.

As for the other category: you have no control over it; it fluctuates and is controlled by the OS.

The Other Category should not be altered, modified, move or deleted nor should it be attempted to be. Doing so may corrupt the OS and rendered the OS inoperative requiring a Wipe and Re-Installation.

The Other category is a potpourri of files which include:

• System temporary files

• macOS system folders

• Archives and disk images (.zip, .iso, etc. - often found in the Downloads folder)

• Personal user data

• Files from the user’s library (Application Support, iCloud files, screensavers, etc.)

• Cache files

• Fonts, plugins, extensions

• Other files that are not recognized by a Spotlight search

• Media files that cannot be classified by Spotlight as a media file because they are located inside of a package

They can be located anywhere on your hard drive. The files that you have control over are located in the Documents, Downloads, Pictures, Music and Movies folders.  You can use either of these two free apps, GrandPerspective  or OmniDiscSweeper, to find the largest files on your drive so you can determine if they can be deleted or moved to an external HD for storage.  

There were to Links embedded in earlier posting for Applications that are safe to use. They can be used to identify large files and their location. It falls upon the User to Delete or move to an external drive for latter usage.