How could I clear the Input::post's values after submit?
Example:
I saved the information in db and I back to the form to a new register (same form), but as the post already loaded values are displayed in the fields.
I tried to use Security::clean_input() but not work.
I solved using $_POST['name'] = ""; or redirecting to itsself.
It is best practice to redirect away with a 'success' messsage of some sort after processing a POST. If only to prevent people from reloading the page (which with your code will cause a second post request with the same data).