gistfile1.php

function onx_reset_faceted_menus ()
{
    if ( isset( $_GET['reset'] ) && class_exists( 'Shopp' ) )
    {
    	// the part of the Shopp Object that holds the facet filtering info, make it empty
    	ShoppStorefront()->browsing = array();
    	
    	// get the current url
    	$url = explode( '?', onx_full_url() );
    	
    	// redirect to the current url, without the extra vars
    	wp_redirect( $url[0] ); exit;
    }
} // end onx_reset_faceted_menus
add_action('wp','onx_reset_faceted_menus',1);