[development] Tmp directory

Hi all, I’m working with Drupal for several months, and today I’v noticed that in the “Tmp” directory (which holds the files till the uploading process complete), There are several “old” files. As I understand this phenomenon, these files are files that their upload-process wasn’t completed successfully , And from some reason they were forgotten in the temporary library… even cron run didn’t delete them. Is there any built-in way to get rid of that unnecessary files? Many thanks! Miriam