Yes, it’s safe to clean up your Mac’s startup disk as long as you only delete personal data and apps. Avoid deleting system data, except for cache files. Here are some safe ways to clear your startup disk:
Clear cache files
Empty your Trash folder
Delete old downloads
Find and eliminate duplicate files
Uninstall apps you don’t use
Delete old and large files
Delete backups you don’t need
Utilize cloud storage features
You can also use a Mac disk space analyzer to automatically get rid of all these junk files and unnecessary system data without manually going through them yourself.