none of your other form elements have a dynamic value, so why not just remove the Dynamic value from the set value equal to option for the list on the results page?
to reset the search, add the following link to the results page:
<a href="products_Results.php?reset=true">Clear Search</a>
then add the following code at line 1:
<?php
@session_start();
if(isset($_GET['reset']) && $_GET['reset'] == "true") {
if(isset($_SESSION["WADbSearch1_products_Results"])) unset($_SESSION["WADbSearch1_products_Results"]);
}
?>