Terri Writes: I’m looking for ways to improve sluggish performance on my computers. I heard that emptying ~/Library/Caches/ can be helpful. Is it safe to also delete the system-level /Library/Caches/ folder?
Generally speaking, it is safe to delete anything in any “Cache” folder managed by OS X. In your case, both the user level (~/Library/Caches/) and system level (/Library/Caches/) folders fit this description. To minimize risk, however, make sure you quit all apps before trashing the folders and then reboot immediately afterwards.
Onyx will automatically clean all your caches and more.
While it’s certainly fine to do this yourself, free apps like Onyx can do this (and more) for you automatically.