title: PHP - Fast way to strip all characters not displayable in browser from utf8 string
body: <p>I've got a little messy database containing names of many institutions around the world.</p>
  
  <p>I want to display them including national characters, but without invalid characters - those displayed in firefox as unicode numbers.</p>
  
  <p>How to filter them out?</p>
  
  <p>Database has utf8 encoding, but some strings were inserted with wrong encodings or were a mess already in sources.</p>
  
  <p>I do not want to fix the database - it's too big. I want to just filter it out - "out of sight out of mind"</p>