I sand the salved edges with a beltsander after the first filler coat of epoxy. Be very carefull though! This knocks down the protruding edge so that you don't need so many filler coats afterwards. Scraping the glass itself with a scraper is too hard and inefficient. The buildup of the filler epoxy coats (two to three layers) is then feathered with a sharp scraper into the finished deck or hull. Do it the next day while the epoxy is still quite soft. If you feather it with a sander it will cut into the deck glass. Of course it needs to be sanded but I am talking only about the line between the old and new epoxy.Check the link below how I bond and glass the deck and hull together. Section 14 of the workshop shows similar situation while building the cockpit rim. I hope it helps. Vaclav