I scrape old glue off with a dull knife, just be careful you don't dig into the anodizing on the shaft.
I'm trying some of those new Blazer vanes, they seem to stabilize the arrow very well. They are made from a thicker, tougher material than most vanes, and shooting them through my Whisker Biscuit hasn't had any effect on them yet. I mounted them with a straight offset.