Regular expressions with ereg_replace

[ponticello]

I'm trying to clean up a string (get rid of special characters, but preserve spaces, and remove trailing spaces) My solution (below) works, but I have a feeling it could be done more elegantly. Suggestions would be greatly appreciated.

function clean($input) {
$output = ereg_replace("['\"!@#$%^{&/()_=`-]{1,9}} ", " ", $input);
$output = ereg_replace(" +", " ", $output);
$output = ereg_replace(" $", "", $output);
return $output;
}

[Anon]

look at the trim(), ltrim(), rtrim(), and chop() functions for removing whitespace.