This prep chart should help answer some of those questions: http://www.nutriliving.com/infographics/extraction-prep-chart. I always peel my oranges before Blasting them, but you can leave some of the skin on. Too much makes the Blast bitter, but some people like it. I use raw beets, carrots and onions, just be careful with how much onion you add, it has a very strong flavor. Beans always must be cooked before adding to your Blast.