Download CCleaner http://www.piriform.com/ccleaner/download/standard
Download CCleaner Enhancer http://thewebatom.net/blog/software-updates/ccleaner-enhancer-1-3-released/
Install. Both are freeware but be aware of the program(s) asking to install toolbars.
Run CCleaner and check the appropriate boxes, alternatively check all the boxes. CCleaner is well recommended by all and sundry and is considered safe to use.