You can squeeze more wax out of the cocoons, but it will be HOT. I generally just pitch them at that point. I leave enough black stuff in the melter to draw heat faster when the sun comes out and then scrape it out of the way or take some out so the good stuff can melt. Gotta love the sun for melting wax and leaving it a nice bright color.
One more idea if you need firestarters. You can take squares of fabric, wrap the gunk up and squeeze it out so the wax saturates the fabric, then pitch the cocoon garbage and you have a nice firestarter. I love them.