A security question about xss_clean

[eluser]Zorancho[/eluser]
Hi to all.
I have one security question about the xss_clean function in CI. I know if global xss filter is set to true in the config file it will automatically clean all $_GET, $_POST and $_COOKIE data, but what about when i want to have safe output. I am using this function in my helper and i have global xss filtering turned to TRUE in the config.

Code:

function safe_output($value)
{
    $value = xss_clean($value);
    $value = mb_convert_encoding($value, 'UTF-8', 'UTF-8');
    $value = htmlentities($value, ENT_QUOTES, 'UTF-8');
    return $value;
}

Is this a good practice to do it or just a waste of time?