"Other Storage" can be cleaned?

Freeing up Drive Space

It is generally considered ‘best practice’ to alway keep at least 15% to 20% of the Total Drives’ Capacity to be kept as Empty Space, to allow the system to do general housekeeping tasks. Allowing the computer to drop below these levels will eventually cause reduced or poor system performance.

The following links can assist in identifying what is taking up space on the Internal Drive and provide possible ways to remove data that is using excessive amounts of drive space. 

➡️  Rebuild the Spotlight index on your Mac

➡️  What is “Other” storage on a Mac, and how can I clean it out?

➡️  Free up storage space on your Mac

➡️  OmniDiskSweeper Safe to use

➡️  GrandPerspective 

➡️  How to delete Time Machine snapshots on your Mac 

➡️  See used and available storage space on your Mac

➡️  Locate backups of your iPhone, iPad, and iPod touch

Note - If a user is using cloning software like Carbon Copy Cloner - it is suggested to adjust the Safety Net Feature in this software. It may be making additional Snap Shots that are not being Cloned to the External Drive. If this is the case, the Snap Shots could also be using additional space on the drive. 

Very good info provided by Randall_2023. The Other Storage are files that don't fit in the categories defined. This will include the Downloads Folder, Desktop Folder, Other Users at  > System Settings > Users & Groups, Extensions, or Caches.

The Cache files are used to speed up app usage by storing frequently used information and for the most part are managed well. They can take up a large amount of disk space and for apps you don't even use anymore, you could delete without any affects on performance. Paste this location into Finder > Go > Go to folder:

~/Library/Caches

I Would also like to suggest to NOT use any cleaner software as we have seen many times in these forums the problems they have caused.