Personally, I would not go the tape route at all. Take a wet washcloth and gently swirl around the eye and see if any of that "stuff" comes off. It may be something it just rubbed against. If it's a retained eyecap, it should come off at a bit of rubbing. If it's a dented eyecap, it's just the result of low humidity and shouldn't be a problem. Otherwise, if it's like some odd looking infection like thing, you should definately get it to a vet.