Remove non-utf8 characters from string

Question

Im having a problem with removing non-utf8 characters from string, which are not displaying properly. Characters are like this 0x97 0x61 0x6C 0x6F (hex representation)

Answer 1

How about iconv:

http://php.net/manual/en/function.iconv.php

Haven't used it inside PHP itself but its always performed well for me on the command line. You can get it to substitute invalid characters.