WordPress function to remove unnecessary classes from menu items.

clean-menu-classes.php

<?php
function cleanname($v) {
		$v = preg_replace('/[^a-zA-Z0-9s]/', '', $v);
		$v = str_replace(' ', '-', $v);
		$v = strtolower($v);
		return $v;
	}
	//	Reduce nav classes, leaving only 'current-menu-item'
	function nav_class_filter( $var ) {
	return is_array($var) ? array_intersect($var, array('current-menu-item')) : '';
	}
	add_filter('nav_menu_css_class', 'nav_class_filter', 100, 1);
	//	Add page slug as nav IDs
	function nav_id_filter( $id, $item ) {
	return 'nav-'.cleanname($item->title);
	}
	add_filter( 'nav_menu_item_id', 'nav_id_filter', 10, 2 );
?>