Comment supprimer tous les fichiers d'un projet

For future projects, consider creating a folder dedicated to it.  Then, in preferences, ensure that the scratch disks are set to "same as project".  You can make subfolders for the various assets.  When the project is complete, the entire folder can be deleted or transfered to long term storage media.  

Along with using the file manager to delete the obvious project files, many or most of the temporary files can be deleted by using the "Delete Rendered Files for All Projects" choice under the Timeline menu.