sS cleanSkypeMsg(S content) {
  LS tok = htmlTok(content);
  new StringBuilder out;
  for (int i = 0; i < l(tok); i++) {
    if (odd(i)) {
      S tag = getTag(tok.get(i));
      if (!eqicOneOf(tag, "b", "i", "at")) {
        // skip any other tags
        
        if (eqic(tag, "ss")) out.append(":" + tagParam(tok.get(i), "type") + ":");
        
        int j = findEndOfContainerTag(tok, i);
        i = j < 0 ? l(tok) : j-1;
      }
    } else
      out.append(htmlDecode(tok.get(i));
  }
  ret str(out);
}