Success - Thanks! Two clarifications please.
That worked.  Thanks!  In an attempt to understand I have 2 questions:
1) Why wouldn't that be the default behavior?  Why would I ever want the items left in the cart?  Did I do something wrong to cause this?
2) *** solved myself - I think:  I just included the first portion of the code you provided - the part to unset the session variables and left out the part that destroys the cookie and the session and the below problem is gone*** 
When I use the browser to print the pp_checkout_success screen, the end of the printout includes a warning which I think may be a result of killing the session.  Can I do something to eliminate this warning since I encourage buyers to do this printout for their records?  The warning and added code are listed below.
Warning: Cannot modify header information - headers already sent by (output started at C:xampp\JoeBagATonerRoot\pp_checkout_success.php:110) in C:...same path... on line 312.
Line 312 is the close paren near the end of the code you provided (marked below):
<?php 
// Initialize the session. 
// If you are using session_name("something"), don't forget it now! 
session_start(); 
// Unset all of the session variables. 
$_SESSION = array(); 
// If it's desired to kill the session, also delete the session cookie. 
// Note: This will destroy the session, and not just the session data! 
if (ini_get("session.use_cookies")) { 
    $params = session_get_cookie_params(); 
    setcookie(session_name(), '', time() - 42000, 
        $params["path"], $params["domain"], 
        $params["secure"], $params["httponly"] 
    );  <--------------------------------------------------------------------line 312
} 
// Finally, destroy the session. 
session_destroy(); 
?> 
Many thanks for your able assistance.  Dave

 














