ISO-8859-1 to UTF-8 using iconv (qualifiers: //TRANSLIT, //IGNORE, none) on an HTML page with a charset=utf-8 meta tag.

Original: This is the Euro symbol '€'.
TRANSLIT: This is the Euro symbol '€'.
IGNORE : This is the Euro symbol '€'.
none : This is the Euro symbol '€'.

& euro; or & #x20ac; bluntly gets the job done for a str_replace -- € or €
MB_CONVERT_ENCODING: This is the Euro symbol '€'.



Original: This is some German 'Weiß, Goldmann, Göbel, Weiss, Göthe, Goethe und Götz'.
TRANSLIT: This is some German 'Weiß, Goldmann, Göbel, Weiss, Göthe, Goethe und Götz'.
IGNORE : This is some German 'Weiß, Goldmann, Göbel, Weiss, Göthe, Goethe und Götz'.
none : This is some German 'Weiß, Goldmann, Göbel, Weiss, Göthe, Goethe und Götz'.

MB_CONVERT_ENCODING: This is some German 'Weiß, Goldmann, Göbel, Weiss, Göthe, Goethe und Götz'.