where to place ob_end_clean?

Hello is it ok to put ob_end_clean in the functions.php file of my template and will it work? I have heard that it should go into wp/index.php but I would prefer no to change core content.

if(!ob_start("ob_gzhandler")){
		if(substr_count($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')) {
			ob_end_clean();
			ob_start("ob_gzhandler_no_errors");
		}else{
			ob_end_clean();
			ob_start();
		}
	}