Any Blogger users out there?

I come back from a short break and find five comments on recent posts in Chinese advertising what I presume, having not dared to click, are sites of an 'adult' nature. This happens from time to time. The puzzle is that I have specifically set up this blog to report comments but only one in every ten or so Chinese ones gets sent to me. Do any of my Blogger-using readers find this happens?

The last time, the frequency became unbearable and I disabled commenting by unregistered users, which resolved it. This time, the comments are from named users so I suspect that won't work. In any case, our anonymous and unregistered commenters add value to the discussion, so I'm not willing to remove them in order to deal with this relatively minor problem. But if any Blogger-using readers have experienced this and know an easy way to block the dodgy commenters, or at least to increase the likelihood I get told about them, I'm all ears.