I have a CSS file that looks fine when I open it using gedit, but when it's read by PHP (to merge all the CSS files into one), this CSS has the following characters prepended to it: 
PHP removes all whitespace, so a random  in the middle of the code messes up the entire thing. As I mentioned, I can't actually see these characters when I open the file in gedit, so I can't remove them very easily.
I googled the problem, and there is clearly something wrong with the file encoding, which makes sense being as I've been shifting the files around to different Linux/Windows servers via ftp and rsync, with a range of text editors. I don't really know much about character encoding though, so help would be appreciated.
If it helps, the file is being saved in UTF-8 format, and gedit won't let me save it in ISO-8859-15 format (the document contains one or more characters that cannot be encoded using the specified character encoding). I tried saving it with Windows and Linux line endings, but neither helped.