Dec 27, 2019 AppCleaner Image: FreeMacSoft. Cleaning up your Mac is an integral part of desktop maintenance, and removing unwanted apps can go a long way in keeping your machine feeling snappy as it ages.
Mac's don't need defragging as OS X automatically writes 2Gb or below sized files to one contiguous space on the drive. There are certain cases where's it's needed to free up a large spaces on the drive, but not something everyone has to do.
How to clean up system storage on Mac with CleanMyMac X: Download CleanMyMac X for free here. Run the app and go to System Junk. Press Clean to get rid of all junk. Now your Mac looks much better!
Total PC Cleaner, as the name suggests, is an all-in-one PC cleaner app with which you can optimize and clean up your system with relative ease. With Total PC Cleaner you can clear up the system cache, application cache, mail cache, office cache, browser cache, downloads and large files.
Cleaner – best Mac cleaner software. One of the best Mac cleaner software is also free on iTunes as well. This all in one tool can help you clean up all the junk in your Mac and speed up the performance too. It can clean all the catch files, clean browser catch, clean the trash and remove anything that left behind after uninstalling an app.
Far as other Mac maintainence, there really isn't any except to backup one's files regularly. Keeping Software Updated and run a web browser check to make sure the plug-ins are current.
For Safari and Flash, this check is more accurate
Most of those cleaning programs are junk, especially MacKeeper.
If your friend got onto your computer and visited a bunch of adult sites, then I would recommend something like OnyX, doing ALL the cleaning and maintenance aspects and rebooting, perhaps followed by a Disk Utility Erase free space.
CCleaner beta is out for OS X, used on PC's and combines cleaning and scrubbing of the drive if setup correctly.
If your interested in performance, read my post here