Thanks Meter 30
Join Date: Jun 2009
Location: Boynton Beach, FL
Well when you uninstall an application you not only have the .apk in /data/app/ but the application data in /data/data/ which is removed when you properly uninstall the application, not just deleting the apk. The "cache" you are seeing is browser, maps etc. data. You can manually do this in application manager by clicking the name then clear cache.
The only extra data you might have would be if the application has data on the sdcard which I find most applications do not remove if it's an external download such as skins. So there really is no need for any type of cleaning tools, none of which would clean out anything on /system/ unless it's a rooted application so there should be no need for that.