Arne, the Gougeon Bros suggest running a sharp knife over the overlap, cutting through both layers of cloth and then removing the excess, while the glue is still flexible, but no longer wet. The trouble with this is that you have to get it at exactly the right time, which is difficult when other things like cooking, washing, cleaning, shopping, sleeping, etc, all have to be attended to. So what I do is try to get it before it cures hard and scrape or plane the bump until it's flat. If you do it correctly, the join becomes invisible.