More than one would be very happy if there was a Purity for reality, but I am afraid that the free exhaustive cleaning at the moment is on computers with programs like CCleaner on Windows or this Purity on Mac.
From my point of view it is a very good application since it has a simply spectacular degree of cleanliness, being able to empty things as diverse as Adium logs, Safari sessions or the system cache.
The application uses a classic Mac OS X interface so there is not much problem here either. Free and functional, there is little more to say - to download, touch -.
Download | Purity