code: private static String cleanString(String field) {
          int size = field.length();
          StringBuilder sb = new StringBuilder(size);
          for (int i = 0; i < size; i++) {
              char nextChar = field.charAt(i);
              switch (nextChar) {
              case HttpConstants.COLON:
              case HttpConstants.COMMA:
              case HttpConstants.EQUALS:
              case HttpConstants.SEMICOLON:
              case HttpConstants.HT:
                  sb.append(HttpConstants.SP_CHAR);
                  break;
              case HttpConstants.DOUBLE_QUOTE:
                  // nothing added, just removes it
                  break;
              default:
                  sb.append(nextChar);
                  break;
              }
          }
          return sb.toString().trim();
      }
docs: Clean the String from any unallowed character
  
  @return the cleaned String