In that hidden menu, you will choose Restore File System. In the sub menu options you can choose Rebuild Database. This will effectively clean your system of corrupted files as it detects them, removing it permanently. One word of caution though, is that you have to refrain from using Restore PS3 System, if you only want get rid of those stubborn corrupt files. That's because choosing that one will wipe out everything that is inside your ps3, including saved game files and others.