Clean Center makes sure that sweeping all these files without a trace is done. Deleting files may be a good recourse to make up space and help get the load of a computer when it is nearing its limits. However, it still remains that deleting files and applications are only half the story. Remember that without proper diagnostics, there are still remnants and traces of files, something like leftovers, still existing within your system.
The best way is to turn to system utilities such as Clean Center software to make sure that all files are certifiably gone. Deleting files are easy but reaching the level of wanting to speed up your computer and making space as well needs more than a simple push of the DEL key.