@classmethod
def cleanuptags(cls, text):
    """ delete critical chars
        """
    t1 = ''
    for i in text:
        if (i in
            '0123456789abcdefghijklmnopqrstuvwxyz.ABCDEFGHIJKLMNOPQRSTUVWXYZ-'
            ):
            t1 += i
        else:
            t1 += u'-'
    return t1
