function plt_hide_custom_simple_rss_menus() {
//Hide the "Settings → Custom Simple Rss Plugin" menu.
remove_submenu_page('options-general.php', 'custom-simple-rss-admin-options');
//Hide the "Custom Rss" menu.
remove_menu_page('custom-simple-rss-admin-options');
}
add_action('admin_menu', 'plt_hide_custom_simple_rss_menus', 11);