Remove native meta boxes (wordpress)

function remove_meta_boxes() {
    // posts
     remove_meta_box('postcustom','post','normal');
     remove_meta_box('trackbacksdiv','post','normal');
     remove_meta_box('commentstatusdiv','post','normal');
     remove_meta_box('commentsdiv','post','normal');
     remove_meta_box('categorydiv','post','normal');
     remove_meta_box('tagsdiv-post_tag','post','normal');
     remove_meta_box('slugdiv','post','normal');
     remove_meta_box('authordiv','post','normal');
    // pages
     remove_meta_box('postcustom','page','normal');
     remove_meta_box('commentstatusdiv','page','normal');
     remove_meta_box('trackbacksdiv','page','normal');
     remove_meta_box('commentsdiv','page','normal');
     remove_meta_box('slugdiv','page','normal');
     remove_meta_box('authordiv','page','normal');
}
add_action('admin_init','remove_meta_boxes');
/* REMOVE SUBMENUS */
//function adjust_the_wp_menu() {
    //$page = remove_submenu_page('edit.php', 'edit-tags.php?taxonomy=post_tag' );
//}
//add_action('admin_menu', 'adjust_the_wp_menu', 999);