User blog comment:JAlbor/Dawnguard: What Everyone Should Know/@comment-98.127.39.121-20120628195216/@comment-26474238-20120628200649

Except for the Elder Scroll (Dragon), I believe you can just sell them to the librarian at the College of Winterhold. As for the exception, you can sell that one to him once you complete the main storyline. Either way, it's not really a problem since quest items don't actually contribute to your weight limit. They say they're 20 pounds, but as long as they're classified as quest items, they'll weight 0.