John, there are several ways to clean up your Mac. You can use third party applications like Onyx to run some maintanances and clean your Mac. Download and install this utility, Onyx from here : http://www.macupdate.com/app/mac/11582/onyx
(Download the correct version of Onyx for your Mac OS X. You can find the different versions in the Related Links in the above page. Make sure you download the correct version of Onyx)
Open Onyx. In Onyx, click on Maintenance
tab. Select Rebuild
tab, check all boxes and then Execute
. The under Cleaning
select System and User and check all boxes on both and Execute. This will fix all system files, clean out old unwanted files and caches etc from your Mac.
Keep Onyx. It is the best maintainance utility out there.
You can also run Disk Utility to fix any corrupted files. Open Disk Utility from Applications > Utilities folder. In Disk Utility, select your hard disk in the left column, then under First Aid tab click Verify Disk, then Repair Disk. Then click Repair Permissions. Thats it !
If you have any questions or would like any additional information, please don't hesitate to ask.