Clean variables sent from forms

Hi, I'm trying to perform a database insertion for a new record from data I receive from a HTML form I send the data to the file containing the insertion script and insert the values using the $_POST['variable_name'] every thing works fine, and the record get inserted correctly the problem is when I refresh this page (the one containing the database insertion script) a new record with the same data is inserted in the same table (I'm using an auto increamented id for this table) .. I was wondering if there is a way that I can delete all values sent from the form after the first insertion successeded Thanks in advance