diff --git a/dist/filters/clean_class.filter.php b/dist/filters/clean_class.filter.php
index 7dcda24..3f0f83b 100755
--- a/dist/filters/clean_class.filter.php
+++ b/dist/filters/clean_class.filter.php
@@ -1,5 +1,18 @@
 <?php
 
 $filter = new Twig_SimpleFilter('clean_class', function ($string) {
+  $filters = [
+    ' ' => '-',
+    '_' => '-',
+    '/' => '-',
+    '[' => '-',
+    ']' => '',
+  ];
+  $string = str_replace(array_keys($filters), array_values($filters), $string);
+  $string = preg_replace('/[^\x{002D}\x{0030}-\x{0039}\x{0041}-\x{005A}\x{005F}\x{0061}-\x{007A}\x{00A1}-\x{FFFF}]/u', '', $string);
+  $string = preg_replace([
+    '/^[0-9]/',
+    '/^(-[0-9])|^(--)/'
+  ], ['_', '__'], $string);
   return $string;
 });