[development] How to clear database after a regular interval

Hello geeks, Most of the drupal modules has test site programmed to clear database after a regular interval, i would like to know how it works. I want to do the same for drupal quiz module demo site, The demo site has been hosted at bluehost which has cpanel where i have options to write my own cron and run it, but i have no idea on how to use it for this purpose. Any suggestions and criticisms regarding this will be appreciated. -- Thanks a lot ----------------------------------------- http://ubuntuslave.blogspot.com/