How can I remove strange characters from a string in php?

Sometimes data you get in html / tabbed files comes encoded in the wrong format, and it displays something like:

®

and other characters.  Before you insert this data into a database, or store it, use this function to clean it up:

utf8_decode();

here's the full page that documents the function:

http://php.net/manual/en/function.utf8-decode.php