function _cleanup_query_vars() {
  // Clean out globals to stop them polluting wp and wp_query.
  foreach ( $GLOBALS['wp']->public_query_vars as $v ) {
    unset( $GLOBALS[ $v ] );
  }

  foreach ( $GLOBALS['wp']->private_query_vars as $v ) {
    unset( $GLOBALS[ $v ] );
  }

  foreach ( get_taxonomies( array(), 'objects' ) as $t ) {
    if ( $t->publicly_queryable && ! empty( $t->query_var ) ) {
      $GLOBALS['wp']->add_query_var( $t->query_var );
    }
  }

  foreach ( get_post_types( array(), 'objects' ) as $t ) {
    if ( is_post_type_viewable( $t ) && ! empty( $t->query_var ) ) {
      $GLOBALS['wp']->add_query_var( $t->query_var );
    }
  }
}