Yes you can delete all files and sub folders with digits in names. You will only receive message regarding running X server, that you cant delete his locked file. Also you can delete all files and folders from /tmp, but you must have root privileges. Mandriva will recreate only some of them on next boot. Also there is a boot option "clear /tmp in each boot" or similar. This will ensure erasing of all files and folders in /tmp at each boot. This you can enable at MCC->Boot->Setup how the systems boot-> Then you shut click on "Advanced" button and you will see this option. Then click "Next" and "Finish". Or you can made simple script to erase all files and folders on /tmp on each shutdown of PC. But this will be more difficult to find right place to save such script, because this must be done on each shut down with root privileges with stopped X server.