automatizar el borrado de estas molestas y pesadas entradas

add_action( 'wp_scheduled_delete', 'delete_expired_db_transients' );
 
function delete_expired_db_transients() {
 
    global $wpdb, $_wp_using_ext_object_cache;
 
    if( $_wp_using_ext_object_cache )
        return;
 
    $time = isset ( $_SERVER['REQUEST_TIME'] ) ? (int)$_SERVER['REQUEST_TIME'] : time() ;
    $expired = $wpdb->get_col( "SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE '_transient_timeout%' AND option_value < {$time};" );
 
    foreach( $expired as $transient ) {
 
        $key = str_replace('_transient_timeout_', '', $transient);
        delete_transient($key);
    }
}