function remove_non_utf8_characters() - just a handle function that can take an array or string and strip out those pesky non-utf8 characters that you see (or don't) sometimes.

remove_non_utf8_characters

<?php

/**
*	$data mixed - will accept strings or arrays - the data to be cleaned
*	$key mixed - will accept strings or arrays - if passed in, the array_walk will only clean those fields
*
*/
function remove_non_utf8_characters( $data, $key = null )
{
	// from http://magp.ie/2011/01/06/remove-non-utf8-characters-from-string-with-php/
	$regex = '/[\x00-\x08\x10\x0B\x0C\x0E-\x19\x7F]|[\x00-\x7F][\x80-\xBF]+|([\xC0\xC1]|[\xF0-\xFF])[\x80-\xBF]*|[\xC2-\xDF]((?![\x80-\xBF])|[\x80-\xBF]{2,})|[\xE0-\xEF](([\x80-\xBF](?![\x80-\xBF]))|(?![\x80-\xBF]{2})|[\x80-\xBF]{3,})/S';

	if ( is_array( $data ) )
	{
		array_walk( $data, function( &$array ) use ($key, $regex) {
			if ( !empty( $key ) )
			{
				if ( !is_array( $key ) )
				{
					$key = array( $key );
				}

				foreach ( $key AS $k )
				{
					$array[$k] = preg_replace($regex, '$1', $array[$k]);
				}
			}
			else
			{
				foreach ( $array AS &$value )
				{
					// TODO consider going recursive to get even more
					if ( !is_array( $value ) )
					{
						$value = preg_replace($regex, '$1', $value);
					}
				}
			}
		} );
	}
	elseif ( is_string( $data ) )
	{
		$data = preg_replace($regex, '$1', $data);
	}

	return $data;
}