Automated disk cleanup software

Windows built-in disk cleanup tool.

Microsoft Windows has a built-in utility which can discover most typical kinds of junk files on the volume. It would then offer you to remove the files considered useless. The list typically includes temporary files, cached data, crash dumps, and the like. The program provides a detailed description for each class of files it suggests to remove. Some fancy options, like cleaning up the system restore points, are also available.

Third party software.

Other than Microsoft cleanup, plenty of clean-up tools are available from independent vendors. All of those use similar methods to determine if the file is useful or not, deciding it by the file extension. This does not provide a result significantly better than a built-in MS tool, so we recommend that you stick with it. However, if you feel like trying a couple of third-party tools yourself just to be sure, Softpedia disk cleaners section looks like a good starting point.

Automated clean-up limitations.

There is no way the automated program can know for sure whether you need the specific piece of data, or not. Because of this, automated clean-up needs to balance between being too conservative (in which case too little effect is achieved) and being too aggressive (so your data is deleted).

Continue to Disk space usage in RAID.