mirek code, dated 16-May-2008 10:17, added the characters `^~'" to the output.
This function will strip out these extra characters:
<?php
setlocale(LC_ALL, 'en_US.UTF8');
function clearUTF($s)
{
    $r = '';
    $s1 = @iconv('UTF-8', 'ASCII//TRANSLIT', $s);
    $j = 0;
    for ($i = 0; $i < strlen($s1); $i++) {
        $ch1 = $s1[$i];
        $ch2 = @mb_substr($s, $j++, 1, 'UTF-8');
        if (strstr('`^~\'"', $ch1) !== false) {
            if ($ch1 <> $ch2) {
                --$j;
                continue;
            }
        }
        $r .= ($ch1=='?') ? $ch2 : $ch1;
    }
    return $r;
}
?>