In Windows, you will get a lot of applications that can be used to scan and remove unwanted junk files and folders that get deposited in the system due to software installation and removal. These files consume system storage and memory resources and ultimately slow down its performance. Since I am Mac OS user I was looking for a similar solution in this scope. Thankfully I come across MacCleaner-a free junk file cleaner for Mac OS X.
MacCleaner

MacCleaner features
Safari stores your passwords, URL logs, media history, etc. in the browser when you use it to visit the internet from your Mac. MacCleaner can be used to remove all these traces.
It can be used to remove the junk files and folders left behind after installation and un-installation of Mac apps.
Clean IM chat logs and temporary files generated by other OS X applications.
MacCleaner is completely free, but you need to register with their company forum to get a free working serial.
Download MacCleaner here.
Update: It seems that they stopped releasing new versions of MacCleaner. So the app is not longer compatible with Mac OS X Snow Leopard and upcoming Lion. Feel free to browse through our old archives to find another freeware Mac applications.

Where do I download it
this cleaner is just what I was looking for. Works great.
it is the best junk file remover.
i’ve been looking for this kind of program for a while!!!!
thank you for sharing
I hope this works.
This article is very useful. I have used my Mac for years and did not notice my hard disk is consuming by the useless files. I followed it and cleaned my Mac. Thanks. And I tried to use free MacCleaning to do this as well.