Something I often find quite handy is to clean specific empty tags with a specific attribute (id, class etc).
Code:
<(p|h\d|div|a)\b[^<>]*?(id="blarg")[^<>]*?>([\s\n\r]|&(nb|en|em|thin)sp;|</?br\s*/?>)*</\1>
I cant remember why I use the extra \r\n; but there was a reason... might have just been old QtRegEx