I just got thru gluing the rub rail and Weaver davit hooks on my hypalon dinghy from Avon. I tried all the kinder ways to get the old glue off, but in the end, the best way was a Dremel sanding stone (the cone-shaped worked best for me) on my air-powered dye grinder and a wire brush in my drill. Yes, it sounds harsh, but it really was the only way to get it all off. Just be careful not to go too deep. You'll see the threads start to fray when you've gone too deep.