You can use it to delete cache, to remove a certain number of problematic files and folders, to see the detailed info of your Mac's configuration, to preview the different logs and CrashReporter reports, and much, much more.
It allows you to run miscellaneous system maintenance tasks to configure hidden parameters for Finder, the Dock, Safari, Dashboard, Exposé, and Disk Utility plus many more. OnyX is a Mac maintenance, optimization, and personalization utility for OS X. Its an app for your Mac that helps you keep it running at peak performance. That's why applications like OnyX are so important. Keeping your computer running the way you want it, with all of your wanted and needed startup options, extensions and TSR's can often create a number of challenges that will require some serious tweaking to get right.
Keeping any PC – regardless of OS – isn't always an easy task. Keep your Mac running at top performance with this must have utility.