Clean the WP admin.

clean_wp_admin

// Clean the admin.
function pk_clean_admin () {
    remove_menu_page('edit.php');
    remove_menu_page('upload.php');
    remove_menu_page('edit.php?post_type=page');
    remove_menu_page('edit-comments.php');
    remove_menu_page('options-general.php');
    remove_menu_page('tools.php');
    
    global $submenu;
    unset($submenu['themes.php'][6]);
}
add_action('admin_menu', 'pk_clean_admin');