It's actually very simple to remove factory glue stains. All you need is the eraser from the suede and nubuck kit which you can pick up from a footlocker. Whether it's on suede or nubuck, the eraser does a decent job of removing the glue stain. Now a word of caution, make sure to take care and precision when using the eraser. You don't want to cause any unnecessary damage from trying to clean it yourself.